docs(api): document verification and files on the compare endpoint (#39440)

`GET /repos/{owner}/{repo}/compare/{basehead}` reads `verification` and
`files` (both default true), the same as the commit endpoints do:

```go
verification := ctx.FormString("verification") == "" || ctx.FormBool("verification")
files := ctx.FormString("files") == "" || ctx.FormBool("files")
```

The spec only lists `output`, so generated clients cannot turn either
off. This documents both with the wording the commit endpoints already
use and regenerates the spec.

Co-authored-by: bircni <bircni@icloud.com>

routers/api/v1/repo/compare.go

@@ -48,6 +48,14 @@ func CompareDiff(ctx *context.APIContext) {
 	//   enum:
 	//   - diff
 	//   - patch
+	// - name: verification
+	//   in: query
+	//   description: include verification for every commit (disable for speedup, default 'true')
+	//   type: boolean
+	// - name: files
+	//   in: query
+	//   description: include a list of affected files for every commit (disable for speedup, default 'true')
+	//   type: boolean
 	// responses:
 	//   "200":
 	//     "$ref": "#/responses/Compare"