Add support for exponentiation operator

Add dedicated pattern primarily to support ligatures.

Author: deathaxe

NgxHTML.sublime-syntax

@@ -553,7 +553,7 @@ contexts:
       scope: punctuation.terminator.expression.ngx
     - match: '[!=]==?|[<>]=?'
       scope: keyword.operator.comparison.ngx
-    - match: '[-+*/%]'
+    - match: '\*\*|[-+*/%]'
       scope: keyword.operator.arithmetic.ngx
     - match: '&&|\|\||!'
       scope: keyword.operator.logical.ngx

tests/syntax_test_scopes.component.html

@@ -611,7 +611,7 @@
   https://angular.dev/guide/templates/expression-syntax#what-operators-are-supported
   -->
 
-  {{ - + * / % === !== == != = < <= >= > && || ! ?? }}
+  {{ - + * / % === !== == != = < <= >= > && || ! ?? ** }}
 <!-- ^ keyword.operator.arithmetic.ngx -->
 <!--   ^ keyword.operator.arithmetic.ngx -->
 <!--     ^ keyword.operator.arithmetic.ngx -->
@@ -630,6 +630,7 @@
 <!--                                        ^^ keyword.operator.logical.ngx -->
 <!--                                           ^ keyword.operator.logical.ngx -->
 <!--                                             ^^ keyword.operator.null-coalescing.ngx -->
+<!--                                                ^^ keyword.operator.arithmetic.ngx -->
 
   <!-- ternary -->
   {{ foo ? bar : baz }}