Link to master version of doc when editing (#262)

* Ensure Edit this Doc links always point to the master source of truth, and not a particular version

* Only show Edit this Doc link if editUrl has been set

lib/core/Doc.js

@@ -20,18 +20,28 @@ const translateThisDoc = translate(
 // inner doc component for article itself
 class Doc extends React.Component {
   render() {
-    let editLink = !this.props.version &&
-      this.props.config.editUrl && (
+    let docSource = this.props.source;
+
+    if (this.props.version && this.props.version !== 'next') {
+      // If versioning is enabled and the current version is not next, we need to trim out "version-*" from the source if we want a valid edit link.
+      docSource = docSource.match(new RegExp(/version-.*\/(.*\.md)/, 'i'))[1];
+    }
+
+    let editLink = this.props.config.editUrl && (
       <a
         className="edit-page-link button"
-          href={this.props.config.editUrl + this.props.source}
+        href={this.props.config.editUrl + docSource}
         target="_blank">
         {editThisDoc}
       </a>
     );
-    if (this.props.language != 'en') {
-      editLink = !this.props.version &&
-        this.props.config.translationRecruitingLink && (
+
+    // If internationalization is enabled, show Recruiting link instead of Edit Link.
+    if (
+      this.props.language != 'en' &&
+      this.props.config.translationRecruitingLink
+    ) {
+      editLink = (
         <a
           className="edit-page-link button"
           href={

lib/core/DocsLayout.js

@@ -52,6 +52,7 @@ class DocsLayout extends React.Component {
                     this.props.metadata.title
                   : this.props.metadata.title
               }
+              version={metadata.version}
               language={metadata.language}
             />
             <div className="docs-prevnext">