markdown: add strikethrough and blockquote captures

CONTRIBUTING.md

@@ -192,7 +192,8 @@ Mainly for markup languages.
 @text.underline        ; underlined text
 @text.strike           ; strikethrough text
 @text.title            ; text that is part of a title
-@text.literal          ; literal or verbatim text
+@text.literal          ; literal or verbatim text (e.g., inline code)
+@text.quote            ; text quotations
 @text.uri              ; URIs (e.g. hyperlinks)
 @text.math             ; math environments (e.g. `$ ... $` in LaTeX)
 @text.environment      ; text environments of markup languages

queries/markdown/highlights.scm

@@ -53,6 +53,8 @@
 (task_list_marker_unchecked) @text.todo.unchecked
 (task_list_marker_checked) @text.todo.checked
 
+(block_quote) @text.quote
+
 [
   (block_continuation)
   (block_quote_marker)

queries/markdown_inline/highlights.scm

@@ -13,6 +13,8 @@
 
 (strong_emphasis) @text.strong
 
+(strikethrough) @text.strike
+
 [
   (link_destination)
   (uri_autolink)
@@ -36,6 +38,7 @@
 (inline_link ["[" "]" "(" ")"] @punctuation.delimiter)
 (shortcut_link ["[" "]"] @punctuation.delimiter)
 
+; Conceal codeblock and text style markers
 ([
   (code_span_delimiter)
   (emphasis_delimiter)