feat(textproto): Add Textproto parser and queries (#5402)

* Add textproto parser and queries

* remove extra newline

* Apply suggestions from code review

Co-authored-by: ObserverOfTime <chronobserver@disroot.org>

---------

Co-authored-by: ObserverOfTime <chronobserver@disroot.org>

queries/textproto/folds.scm

@@ -0,0 +1,5 @@
+[
+  (message_value)
+  (scalar_list)
+  (message_list)
+] @fold

queries/textproto/highlights.scm

@@ -0,0 +1,18 @@
+(string) @string
+
+(field_name) @field
+
+(comment) @comment
+
+(number) @number
+; For stuff like "inf" and "-inf".
+(scalar_value [ (identifier) (signed_identifier) ]) @number
+
+[
+  (open_squiggly)
+  (close_squiggly)
+  (open_square)
+  (close_square)
+  (open_arrow)
+  (close_arrow)
+] @punctuation.bracket

queries/textproto/indents.scm

@@ -0,0 +1,7 @@
+(message_value) @indent.begin
+(message_value (close_squiggly) @indent.branch)
+
+(scalar_list) @indent.begin
+(scalar_list (close_square) @indent.branch)
+(message_list) @indent.begin
+(message_list (close_square) @indent.branch)