feat: add the muttrc parser

queries/muttrc/highlights.scm

@@ -0,0 +1,53 @@
+; Comments
+(comment) @comment @spell
+
+; General
+(int) @number
+
+(string) @string
+
+[
+  (map)
+  (object)
+  (composeobject)
+  (color)
+  (attribute)
+] @string.special
+
+(quadoption) @boolean
+
+(path) @string.special.path
+
+(regex) @string.regexp
+
+[
+  (option)
+  (command_line_option)
+] @variable.builtin
+
+(command) @keyword
+
+(source_directive
+  (command) @keyword.import)
+
+(uri) @string.special.url
+
+(key_name) @constant.builtin
+
+(escape) @string.escape
+
+(function) @function.call
+
+; Literals
+[
+  "<"
+  ">"
+] @punctuation.bracket
+
+"," @punctuation.delimiter
+
+[
+  "&"
+  "?"
+  "*"
+] @character.special

queries/muttrc/injections.scm

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+((regex) @injection.content
+  (#set! injection.language "regex"))
+
+((shell) @injection.content
+  (#set! injection.language "bash"))
+
+((comment) @injection.content
+  (#set! injection.language "comment"))