Replace "#if __clang__" by "#if __has_feature(attribute_analyzer_noreturn)" to be consistent with all other snippets on this page.

Patch by Jean-Daniel Dupas!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@118603 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/www/analyzer/annotations.html b/www/analyzer/annotations.html
index 5184aed..f43e361 100644
--- a/www/analyzer/annotations.html
+++ b/www/analyzer/annotations.html
@@ -442,7 +442,7 @@
 
 <pre class="code_example">
 #ifndef CLANG_ANALYZER_NORETURN
-#if __clang__
+#if __has_feature(attribute_analyzer_noreturn)
 <span class="code_highlight">#define CLANG_ANALYZER_NORETURN __attribute__((analyzer_noreturn))</span>
 #else
 #define CLANG_ANALYZER_NORETURN