Syntax highlighting for Elixir module names and atoms (#166)

Improved syntax highlighting for Elixir atoms and module names using
scopes provided by the JakeBecker.elixir-ls [1,2,3] extension.
The scopes also include the VSCode extension ID to document that the
added scopes are only available for the specific extension with the
given ID and not supported by VSCode out-of-the-box.

[1]: https://marketplace.visualstudio.com/items?itemName=JakeBecker.elixir-ls
[2]: https://github.com/JakeBecker/vscode-elixir-ls
[3]: https://github.com/JakeBecker/vscode-elixir-ls/blob/master/syntaxes/elixir.json

Co-authored-by: Arctic Ice Studio <development@arcticicestudio.com>
Resolves GH-165

themes/nord-color-theme.json

@@ -694,6 +694,36 @@
         "foreground": "#81A1C1"
       }
     },
+    {
+      "name": "[Elixir](JakeBecker.elixir-ls) module names",
+      "scope": "entity.name.type.module.elixir",
+      "settings": {
+        "foreground": "#8FBCBB"
+      }
+    },
+    {
+      "name": "[Elixir](JakeBecker.elixir-ls) module attributes",
+      "scope": "variable.other.readwrite.module.elixir",
+      "settings": {
+        "foreground": "#D8DEE9",
+        "fontStyle": "bold"
+      }
+    },
+    {
+      "name": "[Elixir](JakeBecker.elixir-ls) atoms",
+      "scope": "constant.other.symbol.elixir",
+      "settings": {
+        "foreground": "#D8DEE9",
+        "fontStyle": "bold"
+      }
+    },
+    {
+      "name": "[Elixir](JakeBecker.elixir-ls) modules",
+      "scope": "variable.other.constant.elixir",
+      "settings": {
+        "foreground": "#8FBCBB"
+      }
+    },
     {
       "name": "[Go] String Format Placeholder",
       "scope": "source.go constant.other.placeholder.go",