Set lang and dir attributes on root html element (#6981)

As suggested by the Lighthouse accessibility audit tool.

Author: parlough

site/lib/src/layouts/dash_layout.dart

@@ -179,6 +179,12 @@ ga('send', 'pageview');
 
     return Component.fragment(
       [
+        const Document.html(
+          attributes: {
+            'lang': 'en',
+            'dir': 'ltr',
+          },
+        ),
         Document.body(
           attributes: {
             'class': [?bodyClass, ...defaultBodyClasses].toClasses,

site/pubspec.yaml

@@ -7,7 +7,6 @@ environment:
   sdk: ^3.9.0
 
 dependencies:
-  analyzer: 8.1.1
   build: ^4.0.1
   collection: ^1.19.1
   crypto: ^3.0.6