Add test showing unresolved module rename

Author: Nashenas88

crates/ra_ide/src/syntax_highlighting/tests.rs

@@ -9,6 +9,9 @@ use crate::{mock_analysis::single_file, FileRange, TextRange};
 fn test_highlighting() {
     check_highlighting(
         r#"
+use inner::{self as inner_mod};
+mod inner {}
+
 #[derive(Clone, Debug)]
 struct Foo {
     pub x: i32,

crates/ra_ide/test_data/highlighting.html

@@ -35,7 +35,10 @@
 
 .unresolved_reference { color: #FC5555; text-decoration: wavy underline; }
 </style>
-<pre><code><span class="attribute">#</span><span class="attribute">[</span><span class="function attribute">derive</span><span class="punctuation">(</span><span class="attribute">Clone</span><span class="punctuation">,</span><span class="attribute"> Debug</span><span class="punctuation">)</span><span class="attribute">]</span>
+<pre><code><span class="keyword">use</span> <span class="module">inner</span><span class="operator">::</span><span class="punctuation">{</span><span class="self_keyword">self</span> <span class="keyword">as</span> <span class="unresolved_reference declaration">inner_mod</span><span class="punctuation">}</span><span class="punctuation">;</span>
+<span class="keyword">mod</span> <span class="module declaration">inner</span> <span class="punctuation">{</span><span class="punctuation">}</span>
+
+<span class="attribute">#</span><span class="attribute">[</span><span class="function attribute">derive</span><span class="punctuation">(</span><span class="attribute">Clone</span><span class="punctuation">,</span><span class="attribute"> Debug</span><span class="punctuation">)</span><span class="attribute">]</span>
 <span class="keyword">struct</span> <span class="struct declaration">Foo</span> <span class="punctuation">{</span>
     <span class="keyword">pub</span> <span class="field declaration">x</span><span class="punctuation">:</span> <span class="builtin_type">i32</span><span class="punctuation">,</span>
     <span class="keyword">pub</span> <span class="field declaration">y</span><span class="punctuation">:</span> <span class="builtin_type">i32</span><span class="punctuation">,</span>