feat(ziggy): add ziggy parser and queries

[Ziggy](https://github.com/kristoff-it/ziggy) is a data serialization
format used in the zine static site generator.

queries/ziggy/highlights.scm

@@ -0,0 +1,41 @@
+[
+  (true)
+  (false)
+] @constant.builtin
+
+(null) @constant.builtin
+
+[
+  (integer)
+  (float)
+] @number
+
+(struct_field
+  key: (_) @keyword)
+
+(struct
+  name: (_) @type)
+
+(tag) @function
+
+[
+  (string)
+  (line_string)*
+] @string
+
+(comment) @comment
+
+(escape_sequence) @string.escape
+
+"," @punctuation.delimiter
+
+[
+  "["
+  "]"
+  "{"
+  "}"
+  "("
+  ")"
+] @punctuation.bracket
+
+(top_comment) @comment

queries/ziggy/indents.scm

@@ -0,0 +1,10 @@
+[
+  (struct)
+  (map)
+  (array)
+] @indent.begin
+
+[
+  "]"
+  "}"
+] @indent.end