feat: support QDoc

QDoc is Qt's documentation markup: LaTeX-style commands inside comment
blocks, in C++ sources or standalone .qdoc files. A converter now reads
it into what the walker already understands -- sections are headings,
`\c` is a code span, `\note` is a classed paragraph a rule can target,
topic and quoting commands are markup with nothing to lint, and an
unknown command is masked with its text kept. Doc comments in C++
sources lint through `[formats] cpp = qdoc`, with alerts mapped back to
the source.

Closes #784.

Signed-off-by: Joseph Kato <joseph@jdkato.io>

Author: jdkato

internal/core/format.go

@@ -75,6 +75,7 @@ var FormatByExtension = map[string][]string{
 	`\.(?:md|mdown|markdown|markdn|[Rr]md)$`: {".md", "markup"},
 	`\.(?:mdx)$`:                             {".mdx", "markup"},
 	`\.(?:myst)$`:                            {".myst", "markup"},
+	`\.(?:qdoc)$`:                            {".qdoc", "markup"},
 	`\.(?:qmd)$`:                             {".qmd", "markup"},
 	`\.(?:org)$`:                             {".org", "markup"},
 	`\.(?:php)$`:                             {".php", "code"},

internal/lint/fragment.go

@@ -107,6 +107,8 @@ func (l *Linter) lintFragments(f *core.File) error {
 			err = l.lintADoc(f)
 		case ".org":
 			err = l.lintOrg(f)
+		case ".qdoc":
+			err = l.lintQDoc(f)
 		default:
 			return fmt.Errorf("unsupported markup format '%s'", f.NormedExt)
 		}

internal/lint/html.go

@@ -33,6 +33,7 @@ var blockDelimiters = map[string]string{
 	".md":   "\n```\n$1\n```\n",
 	".mdx":  "\n```\n$1\n```\n",
 	".myst": "\n```\n$1\n```\n",
+	".qdoc": "\n\\code\n$1\n\\endcode\n",
 	".qmd":  "\n```\n$1\n```\n",
 	".rst":  "\n::\n\n%s\n",
 	".org":  orgExample,
@@ -87,6 +88,7 @@ var inlineDelimiters = map[string]string{
 	".md":   "`$1`",
 	".mdx":  "`$1`",
 	".myst": "`$1`",
+	".qdoc": `\c {$1}`,
 	".qmd":  "`$1`",
 	".rst":  "``$1``",
 	".org":  "=$1=",

internal/lint/lint.go

@@ -244,6 +244,8 @@ func (l *Linter) lintFile(src string) lintResult {
 			err = l.lintMDX(file)
 		case ".myst":
 			err = l.lintMyST(file)
+		case ".qdoc":
+			err = l.lintQDoc(file)
 		case ".qmd":
 			err = l.lintQuarto(file)
 		case ".rst":