feat: add the zathurarc parser (#5948)

queries/zathurarc/highlights.scm

@@ -0,0 +1,36 @@
+; General
+(path) @string.special.path
+
+(option) @variable.builtin
+
+(command) @keyword
+
+(include_directive
+  (command) @keyword.import)
+
+(mode_name) @type.builtin
+
+(key) @constant
+
+(function) @function.call
+
+(argument) @variable.parameter
+
+; Comments
+(comment) @comment @spell
+
+; Literals
+(int) @number
+
+(float) @number.float
+
+(string) @string
+
+(bool) @boolean
+
+[
+  "<"
+  ">"
+  "["
+  "]"
+] @punctuation.bracket