Add excluded extern-prelude IDE resolution test

Author: Veykril

src/tools/rust-analyzer/crates/ide/src/syntax_highlighting/test_data/highlight_extern_crate.html

@@ -45,7 +45,9 @@
 .invalid_escape_sequence { color: #FC5555; text-decoration: wavy underline; }
 .unresolved_reference    { color: #FC5555; text-decoration: wavy underline; }
 </style>
-<pre><code><span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root default_library library">std</span><span class="semicolon">;</span>
+<pre><code><span class="keyword">extern</span> <span class="keyword">crate</span> <span class="self_keyword crate_root public">self</span> <span class="keyword">as</span> <span class="module crate_root declaration">this</span><span class="semicolon">;</span>
+<span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root default_library library">std</span><span class="semicolon">;</span>
 <span class="keyword">extern</span> <span class="keyword">crate</span> <span class="module crate_root default_library library">alloc</span> <span class="keyword">as</span> <span class="module crate_root declaration">abc</span><span class="semicolon">;</span>
 <span class="keyword">extern</span> <span class="keyword">crate</span> <span class="unresolved_reference">unresolved</span> <span class="keyword">as</span> <span class="module crate_root declaration">definitely_unresolved</span><span class="semicolon">;</span>
+<span class="keyword">extern</span> <span class="keyword">crate</span> <span class="unresolved_reference">test</span> <span class="keyword">as</span> <span class="module crate_root declaration">opt_in_crate</span><span class="semicolon">;</span>
 </code></pre>

src/tools/rust-analyzer/crates/ide/src/syntax_highlighting/tests.rs

@@ -874,14 +874,18 @@ pub fn block_comments2() {}
 fn test_extern_crate() {
     check_highlighting(
         r#"
-//- /main.rs crate:main deps:std,alloc
+//- /main.rs crate:main deps:std,alloc,test extern-prelude:std,alloc
+extern crate self as this;
 extern crate std;
 extern crate alloc as abc;
 extern crate unresolved as definitely_unresolved;
+extern crate test as opt_in_crate;
 //- /std/lib.rs crate:std
 pub struct S;
 //- /alloc/lib.rs crate:alloc
-pub struct A
+pub struct A;
+//- /test/lib.rs crate:test
+pub struct T;
 "#,
         expect_file!["./test_data/highlight_extern_crate.html"],
         false,