ENH Add Linkfield user docs (#287)

sources-docs.js

@@ -14,7 +14,7 @@ module.exports = [
       name: 'docs--5--optional_features/linkfield',
       remote: 'https://github.com/silverstripe/silverstripe-linkfield.git',
       branch: '4.0',
-      patterns: 'docs/en/**'
+      patterns: 'docs/en/!(userguide)/**'
     }
   },
   {

sources-user.js

@@ -9,6 +9,15 @@ module.exports = [
         patterns: `docs/en/**`
     }
   },
+  {
+    resolve: `gatsby-source-git`,
+    options: {
+      name: `user--5--optional_features/linkfield`,
+      remote: `https://github.com/silverstripe/silverstripe-linkfield`,
+      branch: `4`,
+      patterns: `docs/en/userguide/**`,
+    }
+  },
   {
     resolve: `gatsby-source-git`,
     options: {