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/t/thrift.go

@@ -0,0 +1,73 @@
+package t
+
+import (
+	. "github.com/alecthomas/chroma" // nolint
+	"github.com/alecthomas/chroma/lexers/internal"
+)
+
+// Thrift lexer.
+var Thrift = internal.Register(MustNewLexer(
+	&Config{
+		Name:      "Thrift",
+		Aliases:   []string{"thrift"},
+		Filenames: []string{"*.thrift"},
+		MimeTypes: []string{"application/x-thrift"},
+	},
+	Rules{
+		"root": {
+			Include("whitespace"),
+			Include("comments"),
+			{`"`, LiteralStringDouble, Combined("stringescape", "dqs")},
+			{`\'`, LiteralStringSingle, Combined("stringescape", "sqs")},
+			{`(namespace)(\s+)`, ByGroups(KeywordNamespace, TextWhitespace), Push("namespace")},
+			{`(enum|union|struct|service|exception)(\s+)`, ByGroups(KeywordDeclaration, TextWhitespace), Push("class")},
+			{`((?:(?:[^\W\d]|\$)[\w.\[\]$<>]*\s+)+?)((?:[^\W\d]|\$)[\w$]*)(\s*)(\()`, ByGroups(UsingSelf("root"), NameFunction, Text, Operator), nil},
+			Include("keywords"),
+			Include("numbers"),
+			{`[&=]`, Operator, nil},
+			{`[:;,{}()<>\[\]]`, Punctuation, nil},
+			{`[a-zA-Z_](\.\w|\w)*`, Name, nil},
+		},
+		"whitespace": {
+			{`\n`, TextWhitespace, nil},
+			{`\s+`, TextWhitespace, nil},
+		},
+		"comments": {
+			{`#.*$`, Comment, nil},
+			{`//.*?\n`, Comment, nil},
+			{`/\*[\w\W]*?\*/`, CommentMultiline, nil},
+		},
+		"stringescape": {
+			{`\\([\\nrt"\'])`, LiteralStringEscape, nil},
+		},
+		"dqs": {
+			{`"`, LiteralStringDouble, Pop(1)},
+			{`[^\\"\n]+`, LiteralStringDouble, nil},
+		},
+		"sqs": {
+			{`'`, LiteralStringSingle, Pop(1)},
+			{`[^\\\'\n]+`, LiteralStringSingle, nil},
+		},
+		"namespace": {
+			{`[a-z*](\.\w|\w)*`, NameNamespace, Pop(1)},
+			Default(Pop(1)),
+		},
+		"class": {
+			{`[a-zA-Z_]\w*`, NameClass, Pop(1)},
+			Default(Pop(1)),
+		},
+		"keywords": {
+			{`(async|oneway|extends|throws|required|optional)\b`, Keyword, nil},
+			{`(true|false)\b`, KeywordConstant, nil},
+			{`(const|typedef)\b`, KeywordDeclaration, nil},
+			{Words(``, `\b`, `cpp_namespace`, `cpp_include`, `cpp_type`, `java_package`, `cocoa_prefix`, `csharp_namespace`, `delphi_namespace`, `php_namespace`, `py_module`, `perl_package`, `ruby_namespace`, `smalltalk_category`, `smalltalk_prefix`, `xsd_all`, `xsd_optional`, `xsd_nillable`, `xsd_namespace`, `xsd_attrs`, `include`), KeywordNamespace, nil},
+			{Words(``, `\b`, `void`, `bool`, `byte`, `i16`, `i32`, `i64`, `double`, `string`, `binary`, `map`, `list`, `set`, `slist`, `senum`), KeywordType, nil},
+			{Words(`\b`, `\b`, `BEGIN`, `END`, `__CLASS__`, `__DIR__`, `__FILE__`, `__FUNCTION__`, `__LINE__`, `__METHOD__`, `__NAMESPACE__`, `abstract`, `alias`, `and`, `args`, `as`, `assert`, `begin`, `break`, `case`, `catch`, `class`, `clone`, `continue`, `declare`, `def`, `default`, `del`, `delete`, `do`, `dynamic`, `elif`, `else`, `elseif`, `elsif`, `end`, `enddeclare`, `endfor`, `endforeach`, `endif`, `endswitch`, `endwhile`, `ensure`, `except`, `exec`, `finally`, `float`, `for`, `foreach`, `function`, `global`, `goto`, `if`, `implements`, `import`, `in`, `inline`, `instanceof`, `interface`, `is`, `lambda`, `module`, `native`, `new`, `next`, `nil`, `not`, `or`, `pass`, `public`, `print`, `private`, `protected`, `raise`, `redo`, `rescue`, `retry`, `register`, `return`, `self`, `sizeof`, `static`, `super`, `switch`, `synchronized`, `then`, `this`, `throw`, `transient`, `try`, `undef`, `unless`, `unsigned`, `until`, `use`, `var`, `virtual`, `volatile`, `when`, `while`, `with`, `xor`, `yield`), KeywordReserved, nil},
+		},
+		"numbers": {
+			{`[+-]?(\d+\.\d+([eE][+-]?\d+)?|\.?\d+[eE][+-]?\d+)`, LiteralNumberFloat, nil},
+			{`[+-]?0x[0-9A-Fa-f]+`, LiteralNumberHex, nil},
+			{`[+-]?[0-9]+`, LiteralNumberInteger, nil},
+		},
+	},
+))