* prometheus ace editor, template variable support

* minor fix

* support [[var]] notation

* don't remove last ] if token type is string

* Revert "don't remove last ] if token type is string"

This reverts commit bce5b2d56e7d01a63b756b2b989ee9796bcc6711.

* Revert "support [[var]] notation"

This reverts commit 10012f8ffe8cfbec62c37d7e99c7758c8a86ab6d.

* fix token type and regex