docs: Add missing link to aws_lambda_alias

Author: Radek Simko

website/source/layouts/aws.erb

@@ -350,6 +350,9 @@
               <li<%= sidebar_current(/^docs-aws-resource-lambda/) %>>
                   <a href="#">Lambda Resources</a>
                   <ul class="nav nav-visible">
+                      <li<%= sidebar_current("docs-aws-resource-lambda-alias") %>>
+                          <a href="/docs/providers/aws/r/lambda_alias.html">aws_lambda_alias</a>
+                      </li>
                       <li<%= sidebar_current("docs-aws-resource-lambda-function") %>>
                           <a href="/docs/providers/aws/r/lambda_function.html">aws_lambda_function</a>
                       </li>