Fixing a typo. Found by Kevin André!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42956 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LangRef.html b/docs/LangRef.html
index 10fb2e6..dac34f8 100644
--- a/docs/LangRef.html
+++ b/docs/LangRef.html
@@ -1296,7 +1296,7 @@
 <h5>Overview:</h5>
 
 <p>Opaque types are used to represent unknown types in the system.  This
-corresponds (for example) to the C notion of a foward declared structure type.
+corresponds (for example) to the C notion of a forward declared structure type.
 In LLVM, opaque types can eventually be resolved to any type (not just a
 structure type).</p>