Makes version selection better

Covers a few common cases in which the version number can be specified.

Author: aszenz

docs/index.html

@@ -80,7 +80,13 @@
             const RusfmtTagsUrl = 'https://api.github.com/repos/rust-lang/rustfmt/tags';
             const UrlHash = window.location.hash.replace(/^#/, '');
             const queryParams = new URLSearchParams(window.location.search);
-            const versionNumber = null !== queryParams.get('version') ? 'v' + queryParams.get('version') : 'master';
+            const versionParam = queryParams.get('version');
+            const parseVersionParam = (version) => {
+              if (version === 'master') return 'master';
+              if (version.startsWith('v')) return version;
+              return `v${version}`;
+            };
+            const versionNumber = null !== versionParam ? parseVersionParam(versionParam) : 'master';
             new Vue({
               el: '#app',
               data: {