Add regex syntax highlighting for JS and TS (#7851)

<img width="544" alt="SCR-20240215-pvzy"
src="https://github.com/zed-industries/zed/assets/67913738/e4d463a6-1795-4728-ac24-6c8e03e7ea5b">

Release Notes:

- Added support for regex syntax highlighting in `JS` and `TS`.

crates/languages/src/regex/highlights.scm

@@ -0,0 +1,50 @@
+[
+  "("
+  ")"
+  "(?"
+  "(?:"
+  "(?<"
+  ">"
+  "["
+  "]"
+  "{"
+  "}"
+] @punctuation.bracket
+
+(group_name) @property
+
+[
+  (identity_escape)
+  (control_letter_escape)
+  (character_class_escape)
+  (control_escape)
+  (start_assertion)
+  (end_assertion)
+  (boundary_assertion)
+  (non_boundary_assertion)
+] @escape
+
+[
+  "*"
+  "+"
+  "?"
+  "|"
+  "="
+  "!"
+] @operator
+
+(count_quantifier
+  [
+    (decimal_digits) @number
+    "," @punctuation.delimiter
+  ])
+
+(character_class
+  [
+    "^" @operator
+    (class_range "-" @operator)
+  ])
+
+(class_character) @constant.character
+
+(pattern_character) @string