feat: add Doxygen

queries/doxygen/highlights.scm

@@ -0,0 +1,38 @@
+((tag_name) @keyword
+  (#set! "priority" 105))
+
+(identifier) @variable
+
+((tag
+  (tag_name) @_param 
+  (identifier) @parameter)
+  (#any-of? @_param "@param" "\\param"))
+
+(function (identifier) @function)
+
+(function_link) @function
+
+(emphasis) @text.emphasis
+
+"\\a" @tag
+
+[
+  "in"
+  "out"
+  "inout"
+] @storageclass
+
+"~" @operator
+
+[
+  "<a"
+  ">"
+  "</a>"
+] @tag
+
+[
+  ","
+  "::"
+] @punctuation.delimiter
+
+[ "(" ")" "[" "]" ] @punctuation.bracket

queries/doxygen/indents.scm

@@ -0,0 +1 @@
+(document) @indent.auto

queries/doxygen/injections.scm

@@ -0,0 +1,8 @@
+((type) @injection.content
+  (#set! injection.parent))
+
+((function_link) @injection.content
+  (#set! injection.parent))
+
+((link) @injection.content
+  (#set! injection.language "html"))