🐛 Fixed {{meta_title}} output when using data: page.{slug} in routes

refs TryGhost#10082

- meta_title output wrong meta title

Only solves meta_title outout for this use case:

```
routes:
  /:
    data: page.{slug}
    template: t
```

core/server/data/meta/title.js

@@ -34,13 +34,29 @@ function getTitle(data, root, options) {
     } else if (_.includes(context, 'tag') && data.tag) {
         title = data.tag.meta_title || data.tag.name + ' - ' + blogTitle;
     // Post title
-    } else if ((_.includes(context, 'post') || _.includes(context, 'page')) && data.post) {
+    } else if (_.includes(context, 'post') && data.post) {
         if (options && options.property) {
             postSdTitle = options.property + '_title';
             title = data.post[postSdTitle] || '';
         } else {
             title = data.post.meta_title || data.post.title;
         }
+    // Page title v0.1
+    } else if (_.includes(context, 'page') && data.post) {
+        if (options && options.property) {
+            postSdTitle = options.property + '_title';
+            title = data.post[postSdTitle] || '';
+        } else {
+            title = data.post.meta_title || data.post.title;
+        }
+    // Page title v2
+    } else if (_.includes(context, 'page') && data.page) {
+        if (options && options.property) {
+            postSdTitle = options.property + '_title';
+            title = data.page[postSdTitle] || '';
+        } else {
+            title = data.page.meta_title || data.page.title;
+        }
     // Fallback
     } else {
         title = blogTitle + pageString;

core/test/unit/data/meta/title_spec.js

@@ -190,7 +190,7 @@ describe('getTitle', function () {
         title.should.equal('My awesome post!');
     });
 
-    it('should return post title if in page context', function () {
+    it('v0.1: should return post title if in page context', function () {
         var title = getTitle({
             post: {
                 title: 'My awesome page!'
@@ -200,6 +200,16 @@ describe('getTitle', function () {
         title.should.equal('My awesome page!');
     });
 
+    it('v2: should return page title if in page context', function () {
+        var title = getTitle({
+            page: {
+                title: 'My awesome page!'
+            }
+        }, {context: ['page']});
+
+        title.should.equal('My awesome page!');
+    });
+
     it('should return post title if in amp and page context', function () {
         var title = getTitle({
             post: {