Server-side syntax highlighting for all code (#12047)

* Server-side syntax hilighting for all code

This PR does a few things:

* Remove all traces of highlight.js
* Use chroma library to provide fast syntax hilighting directly on the server
* Provide syntax hilighting for diffs
* Re-style both unified and split diffs views
* Add custom syntax hilighting styling for both regular and arc-green

Fixes #7729
Fixes #10157
Fixes #11825
Fixes #7728
Fixes #3872
Fixes #3682

And perhaps gets closer to #9553

* fix line marker

* fix repo search

* Fix single line select

* properly load settings

* npm uninstall highlight.js

* review suggestion

* code review

* forgot to call function

* fix test

* Apply suggestions from code review

suggestions from @silverwind thanks

Co-authored-by: silverwind <me@silverwind.io>

* code review

* copy/paste error

* Use const for highlight size limit

* Update web_src/less/_repository.less

Co-authored-by: Lauris BH <lauris@nix.lv>

* update size limit to 1MB and other styling tweaks

* fix highlighting for certain diff sections

* fix test

* add worker back as suggested

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Lauris BH <lauris@nix.lv>

vendor/github.com/alecthomas/chroma/lexers/c/cython.go

@@ -0,0 +1,135 @@
+package c
+
+import (
+	. "github.com/alecthomas/chroma" // nolint
+	"github.com/alecthomas/chroma/lexers/internal"
+)
+
+// Cython lexer.
+var Cython = internal.Register(MustNewLexer(
+	&Config{
+		Name:      "Cython",
+		Aliases:   []string{"cython", "pyx", "pyrex"},
+		Filenames: []string{"*.pyx", "*.pxd", "*.pxi"},
+		MimeTypes: []string{"text/x-cython", "application/x-cython"},
+	},
+	Rules{
+		"root": {
+			{`\n`, Text, nil},
+			{`^(\s*)("""(?:.|\n)*?""")`, ByGroups(Text, LiteralStringDoc), nil},
+			{`^(\s*)('''(?:.|\n)*?''')`, ByGroups(Text, LiteralStringDoc), nil},
+			{`[^\S\n]+`, Text, nil},
+			{`#.*$`, Comment, nil},
+			{`[]{}:(),;[]`, Punctuation, nil},
+			{`\\\n`, Text, nil},
+			{`\\`, Text, nil},
+			{`(in|is|and|or|not)\b`, OperatorWord, nil},
+			{`(<)([a-zA-Z0-9.?]+)(>)`, ByGroups(Punctuation, KeywordType, Punctuation), nil},
+			{`!=|==|<<|>>|[-~+/*%=<>&^|.?]`, Operator, nil},
+			{`(from)(\d+)(<=)(\s+)(<)(\d+)(:)`, ByGroups(Keyword, LiteralNumberInteger, Operator, Name, Operator, Name, Punctuation), nil},
+			Include("keywords"),
+			{`(def|property)(\s+)`, ByGroups(Keyword, Text), Push("funcname")},
+			{`(cp?def)(\s+)`, ByGroups(Keyword, Text), Push("cdef")},
+			{`(cdef)(:)`, ByGroups(Keyword, Punctuation), nil},
+			{`(class|struct)(\s+)`, ByGroups(Keyword, Text), Push("classname")},
+			{`(from)(\s+)`, ByGroups(Keyword, Text), Push("fromimport")},
+			{`(c?import)(\s+)`, ByGroups(Keyword, Text), Push("import")},
+			Include("builtins"),
+			Include("backtick"),
+			{`(?:[rR]|[uU][rR]|[rR][uU])"""`, LiteralString, Push("tdqs")},
+			{`(?:[rR]|[uU][rR]|[rR][uU])'''`, LiteralString, Push("tsqs")},
+			{`(?:[rR]|[uU][rR]|[rR][uU])"`, LiteralString, Push("dqs")},
+			{`(?:[rR]|[uU][rR]|[rR][uU])'`, LiteralString, Push("sqs")},
+			{`[uU]?"""`, LiteralString, Combined("stringescape", "tdqs")},
+			{`[uU]?'''`, LiteralString, Combined("stringescape", "tsqs")},
+			{`[uU]?"`, LiteralString, Combined("stringescape", "dqs")},
+			{`[uU]?'`, LiteralString, Combined("stringescape", "sqs")},
+			Include("name"),
+			Include("numbers"),
+		},
+		"keywords": {
+			{Words(``, `\b`, `assert`, `break`, `by`, `continue`, `ctypedef`, `del`, `elif`, `else`, `except`, `except?`, `exec`, `finally`, `for`, `fused`, `gil`, `global`, `if`, `include`, `lambda`, `nogil`, `pass`, `print`, `raise`, `return`, `try`, `while`, `yield`, `as`, `with`), Keyword, nil},
+			{`(DEF|IF|ELIF|ELSE)\b`, CommentPreproc, nil},
+		},
+		"builtins": {
+			{Words(`(?<!\.)`, `\b`, `__import__`, `abs`, `all`, `any`, `apply`, `basestring`, `bin`, `bool`, `buffer`, `bytearray`, `bytes`, `callable`, `chr`, `classmethod`, `cmp`, `coerce`, `compile`, `complex`, `delattr`, `dict`, `dir`, `divmod`, `enumerate`, `eval`, `execfile`, `exit`, `file`, `filter`, `float`, `frozenset`, `getattr`, `globals`, `hasattr`, `hash`, `hex`, `id`, `input`, `int`, `intern`, `isinstance`, `issubclass`, `iter`, `len`, `list`, `locals`, `long`, `map`, `max`, `min`, `next`, `object`, `oct`, `open`, `ord`, `pow`, `property`, `range`, `raw_input`, `reduce`, `reload`, `repr`, `reversed`, `round`, `set`, `setattr`, `slice`, `sorted`, `staticmethod`, `str`, `sum`, `super`, `tuple`, `type`, `unichr`, `unicode`, `unsigned`, `vars`, `xrange`, `zip`), NameBuiltin, nil},
+			{`(?<!\.)(self|None|Ellipsis|NotImplemented|False|True|NULL)\b`, NameBuiltinPseudo, nil},
+			{Words(`(?<!\.)`, `\b`, `ArithmeticError`, `AssertionError`, `AttributeError`, `BaseException`, `DeprecationWarning`, `EOFError`, `EnvironmentError`, `Exception`, `FloatingPointError`, `FutureWarning`, `GeneratorExit`, `IOError`, `ImportError`, `ImportWarning`, `IndentationError`, `IndexError`, `KeyError`, `KeyboardInterrupt`, `LookupError`, `MemoryError`, `NameError`, `NotImplemented`, `NotImplementedError`, `OSError`, `OverflowError`, `OverflowWarning`, `PendingDeprecationWarning`, `ReferenceError`, `RuntimeError`, `RuntimeWarning`, `StandardError`, `StopIteration`, `SyntaxError`, `SyntaxWarning`, `SystemError`, `SystemExit`, `TabError`, `TypeError`, `UnboundLocalError`, `UnicodeDecodeError`, `UnicodeEncodeError`, `UnicodeError`, `UnicodeTranslateError`, `UnicodeWarning`, `UserWarning`, `ValueError`, `Warning`, `ZeroDivisionError`), NameException, nil},
+		},
+		"numbers": {
+			{`(\d+\.?\d*|\d*\.\d+)([eE][+-]?[0-9]+)?`, LiteralNumberFloat, nil},
+			{`0\d+`, LiteralNumberOct, nil},
+			{`0[xX][a-fA-F0-9]+`, LiteralNumberHex, nil},
+			{`\d+L`, LiteralNumberIntegerLong, nil},
+			{`\d+`, LiteralNumberInteger, nil},
+		},
+		"backtick": {
+			{"`.*?`", LiteralStringBacktick, nil},
+		},
+		"name": {
+			{`@\w+`, NameDecorator, nil},
+			{`[a-zA-Z_]\w*`, Name, nil},
+		},
+		"funcname": {
+			{`[a-zA-Z_]\w*`, NameFunction, Pop(1)},
+		},
+		"cdef": {
+			{`(public|readonly|extern|api|inline)\b`, KeywordReserved, nil},
+			{`(struct|enum|union|class)\b`, Keyword, nil},
+			{`([a-zA-Z_]\w*)(\s*)(?=[(:#=]|$)`, ByGroups(NameFunction, Text), Pop(1)},
+			{`([a-zA-Z_]\w*)(\s*)(,)`, ByGroups(NameFunction, Text, Punctuation), nil},
+			{`from\b`, Keyword, Pop(1)},
+			{`as\b`, Keyword, nil},
+			{`:`, Punctuation, Pop(1)},
+			{`(?=["\'])`, Text, Pop(1)},
+			{`[a-zA-Z_]\w*`, KeywordType, nil},
+			{`.`, Text, nil},
+		},
+		"classname": {
+			{`[a-zA-Z_]\w*`, NameClass, Pop(1)},
+		},
+		"import": {
+			{`(\s+)(as)(\s+)`, ByGroups(Text, Keyword, Text), nil},
+			{`[a-zA-Z_][\w.]*`, NameNamespace, nil},
+			{`(\s*)(,)(\s*)`, ByGroups(Text, Operator, Text), nil},
+			Default(Pop(1)),
+		},
+		"fromimport": {
+			{`(\s+)(c?import)\b`, ByGroups(Text, Keyword), Pop(1)},
+			{`[a-zA-Z_.][\w.]*`, NameNamespace, nil},
+			Default(Pop(1)),
+		},
+		"stringescape": {
+			{`\\([\\abfnrtv"\']|\n|N\{.*?\}|u[a-fA-F0-9]{4}|U[a-fA-F0-9]{8}|x[a-fA-F0-9]{2}|[0-7]{1,3})`, LiteralStringEscape, nil},
+		},
+		"strings": {
+			{`%(\([a-zA-Z0-9]+\))?[-#0 +]*([0-9]+|[*])?(\.([0-9]+|[*]))?[hlL]?[E-GXc-giorsux%]`, LiteralStringInterpol, nil},
+			{`[^\\\'"%\n]+`, LiteralString, nil},
+			{`[\'"\\]`, LiteralString, nil},
+			{`%`, LiteralString, nil},
+		},
+		"nl": {
+			{`\n`, LiteralString, nil},
+		},
+		"dqs": {
+			{`"`, LiteralString, Pop(1)},
+			{`\\\\|\\"|\\\n`, LiteralStringEscape, nil},
+			Include("strings"),
+		},
+		"sqs": {
+			{`'`, LiteralString, Pop(1)},
+			{`\\\\|\\'|\\\n`, LiteralStringEscape, nil},
+			Include("strings"),
+		},
+		"tdqs": {
+			{`"""`, LiteralString, Pop(1)},
+			Include("strings"),
+			Include("nl"),
+		},
+		"tsqs": {
+			{`'''`, LiteralString, Pop(1)},
+			Include("strings"),
+			Include("nl"),
+		},
+	},
+))