Support more binary assignment operators in templates

angular/angular#62064

@deathaxe does this look about right?

Author: princemaple

NgxHTML.sublime-syntax

@@ -558,7 +558,7 @@ contexts:
       scope: keyword.operator.arithmetic.ngx
     - match: '&&|\|\||!'
       scope: keyword.operator.logical.ngx
-    - match: '='
+    - match: '=|\+=|-=|\*=|/=|%=|\*\*=|&&=|\|\|=|\?\?='
       scope: keyword.operator.assignment.ngx
     - match: \?\?
       scope: keyword.operator.null-coalescing.ngx