Add extension build script

Author: MaximeKjaer

CONTRIBUTING.md

@@ -9,8 +9,6 @@ for Visual Studio Code.
 Make sure you have the following binaries installed:
 
 - [`yarn`](https://yarnpkg.com/en/): to build the project
-- [`vsce`](https://code.visualstudio.com/api/working-with-extensions/publishing-extension):
-  to package the extension for VS Code.
 - [`code`](https://code.visualstudio.com/docs/setup/mac): to launch VS Code from
   the terminal.
 
@@ -50,7 +48,7 @@ changes.
 ```bash
 yarn install
 yarn build
-vsce package
+
 # replace `*` below with the version of the generated vsix file
 code --install-extension scala-*.vsix
 ```

package.json

@@ -54,7 +54,9 @@
     "scripts": {
         "vscode:prepublish": "test -f ./syntaxes/Scala.tmLanguage.json",
         "vscode:publish": "vsce publish --yarn",
-        "build": "ts-node src/typescript/GenerateTmLanguageFile.ts > ./syntaxes/Scala.tmLanguage.json",
+        "build": "npm-run-all build:syntax build:extension",
+        "build:syntax": "ts-node src/typescript/GenerateTmLanguageFile.ts > ./syntaxes/Scala.tmLanguage.json",
+        "build:extension": "vsce package",
         "test": "npm-run-all test:*",
         "test:unit": "vscode-tmgrammar-test -s source.scala -g syntaxes/Scala.tmLanguage.json -t 'tests/unit/**/*.test.scala'",
         "test:snap": "vscode-tmgrammar-snap -s source.scala -g syntaxes/Scala.tmLanguage.json -t 'tests/snap/**/*.test.scala'"