Improve syntax highligting for escaped characters (rescript-lang#929)

* Support escape in tagged templates

* Grammar: use string character escape regex from ts grammar

* Add changelog

Author: DZakh

Diff for: CHANGELOG.md

@@ -22,6 +22,8 @@
 - Handle completion for DOM/element attributes and attribute values properly when using a generic JSX transform. https://github.com/rescript-lang/rescript-vscode/pull/919
 - Highlight tagged template literal functions as functions. https://github.com/rescript-lang/rescript-vscode/pull/920
 - Complete for `type t` values when encountering a `type t` in relevant scenarios. https://github.com/rescript-lang/rescript-vscode/pull/924
+- Highlight escaped sequences as a whole and not only the first character. https://github.com/rescript-lang/rescript-vscode/pull/929
+- Start highlighting escaped sequences in template literals. https://github.com/rescript-lang/rescript-vscode/pull/929
 
 ## 1.38.0
 

Diff for: grammars/rescript.tmLanguage.json

@@ -119,6 +119,10 @@
         }
       ]
     },
+    "string-character-escape": {
+      "name": "constant.character.escape",
+      "match": "\\\\(x[0-9A-Fa-f]{2}|u[0-9A-Fa-f]{4}|u{[0-9A-Fa-f]+}|[0-2][0-7]{0,2}|3[0-6][0-7]?|37[0-7]?|[4-7][0-7]?|.|$)"
+    },
     "string": {
       "patterns": [
         {
@@ -137,8 +141,7 @@
           },
           "patterns": [
             {
-              "name": "constant.character.escape",
-              "match": "\\\\."
+              "include": "#string-character-escape"
             }
           ]
         },
@@ -160,6 +163,9 @@
             }
           },
           "patterns": [
+            {
+              "include": "#string-character-escape"
+            },
             {
               "name": "meta.template.expression",
               "begin": "\\$\\{",
@@ -606,4 +612,4 @@
       "include": "#defaultIdIsVariable"
     }
   ]
-}
+}