Update Elixir syntax to the latest from ElixirLS (#94)

Author: probably-not

package.json

@@ -36,9 +36,16 @@
         "scopeName": "source.elixir",
         "path": "./syntaxes/elixir.json",
         "unbalancedBracketScopes": [
+          "keyword.operator.bitwise.elixir",
+          "keyword.operator.other.unbalanced.elixir",
           "constant.language.symbol.elixir",
-          "entity.name.map-access.elixir"
-        ]
+          "constant.language.symbol.single-quoted.elixir",
+          "constant.language.symbol.double-quoted.elixir",
+          "entity.name.function.call.dot.elixir"
+        ],
+        "embeddedLanguages": {
+          "comment.documentation.heredoc.elixir": "markdown"
+        }
       },
       {
         "language": "eex",