Rewrite the noredzone description, attempting to avoid confusing language.

llvm-svn: 73421
diff --git a/llvm/docs/LangRef.html b/llvm/docs/LangRef.html
index ea75ffc..a79280c 100644
--- a/llvm/docs/LangRef.html
+++ b/llvm/docs/LangRef.html
@@ -1107,7 +1107,7 @@
 
 <dt><tt>noredzone</tt></dt>
 <dd>This attribute indicates that the code generator should not use a
-red zone, even if it would otherwise be supported by the target-specific ABI.
+red zone, even if the target-specific ABI normally permits it.
 </dd>
 
 <dt><tt>noimplicitfloat</tt></dt>