fix(grammar): make brace and keyword separately queryable

grammar.js

@@ -26,20 +26,27 @@ export default grammar({
     content: _ => token(prec(-1, /([^{]|\{[^A-Za-z/])+/)),
 
     block_open: $ => seq(
-      $._block_open_start,
+      "{",
+      $.block_keyword,
+      ":",
       $.block_name,
       optional($.attributes),
       "}",
     ),
 
     block_close: $ => seq(
-      $._block_close_start,
+      "{",
+      "/",
+      $.block_keyword,
+      ":",
       $.block_name,
       "}",
     ),
 
     lang_tag: $ => seq(
-      $._lang_start,
+      "{",
+      $.lang_keyword,
+      ":",
       $.lang_text,
       "}",
     ),
@@ -65,9 +72,8 @@ export default grammar({
     prefix_argument: _ => /[A-Za-z][A-Za-z0-9 _-]*/,
     lang_text: _ => /[^}]+/,
 
-    _block_open_start: _ => /\{[Bb][Ll][Oo][Cc][Kk]:/,
-    _block_close_start: _ => /\{\/[Bb][Ll][Oo][Cc][Kk]:/,
-    _lang_start: _ => /\{[Ll][Aa][Nn][Gg]:/,
+    block_keyword: _ => token(prec(1, /[Bb][Ll][Oo][Cc][Kk]/)),
+    lang_keyword: _ => token(prec(1, /[Ll][Aa][Nn][Gg]/)),
     _space: _ => /[ \t]+/,
   },
 });