Fix typo.

Thanks to Sean Silva for noticing it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192102 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LangRef.rst b/docs/LangRef.rst
index 6a78c14..7ae7e7e 100644
--- a/docs/LangRef.rst
+++ b/docs/LangRef.rst
@@ -614,7 +614,7 @@
 
     @<Name> = alias [Linkage] [Visibility] <AliaseeTy> @<Aliasee>
 
-The linkgage must be one of ``private``, ``linker_private``,
+The linkage must be one of ``private``, ``linker_private``,
 ``linker_private_weak``, ``internal``, ``linkonce``, ``weak``,
 ``linkonce_odr``, ``weak_odr``, ``linkonce_odr_auto_hide``, ``external``. Note
 that some system linkers might not correctly handle dropping a weak symbol that