typescript: Highlight is predicate keyword & ... spread pattern (#17787)

Release Notes:

- Fixed the `is` and `...` highlights for TypeScript

crates/languages/src/tsx/highlights.scm

@@ -181,6 +181,7 @@
   "import"
   "in"
   "instanceof"
+  "is"
   "let"
   "new"
   "of"

crates/languages/src/typescript/highlights.scm

@@ -100,6 +100,7 @@
 ] @punctuation.delimiter
 
 [
+  "..."
   "-"
   "--"
   "-="
@@ -181,6 +182,7 @@
   "import"
   "in"
   "instanceof"
+  "is"
   "let"
   "new"
   "of"