Adjust to switch of formatter implementation from prettier to yaml

We switched the formatter implementation of yaml-language-server to be
based on eemeli/yaml instead of prettier,
since it can provide all the same functionality,
and avoiding the extra dependency on prettier reduces the total size of the language server.

Using prettier to provide formatting support was also a blocker for getting
the formatting to work in the web version of the extension,
since prettier doesn't work well with bundlers.

This PR removes the shim that changed formatting on web to a NO-OP,
since we should now be able to format properly on web.

Signed-off-by: David Thompson <davthomp@redhat.com>

Author: datho7561

.vscodeignore

@@ -21,6 +21,3 @@ CONTRIBUTING.md
 **/**.vsix
 **/**.tar.gz
 test-resources
-!node_modules/prettier/index.js
-!node_modules/prettier/third-party.js
-!node_modules/prettier/parser-yaml.js

webpack.config.js

@@ -31,7 +31,6 @@ const config = {
   devtool: 'source-map',
   externals: {
     vscode: 'commonjs vscode', // the vscode-module is created on-the-fly and must be excluded. Add other modules that cannot be webpack'ed, 📖 -> https://webpack.js.org/configuration/externals/
-    prettier: 'commonjs prettier',
   },
   resolve: {
     // support reading TypeScript and JavaScript files, 📖 -> https://github.com/TypeStrong/ts-loader
@@ -136,7 +135,6 @@ const serverWeb = {
     mainFields: ['browser', 'module', 'main'],
     extensions: ['.ts', '.js'], // support ts-files and js-files
     alias: {
-      './services/yamlFormatter': path.resolve(__dirname, './build/polyfills/yamlFormatter.js'), // not supported for now. prettier can run in the web, but it's a bit more work.
       'vscode-json-languageservice/lib/umd': 'vscode-json-languageservice/lib/esm',
     },
     fallback: {