Rename all references to old mailing lists to new lists.llvm.org address.

llvm-svn: 243999
diff --git a/llvm/docs/TableGen/LangIntro.rst b/llvm/docs/TableGen/LangIntro.rst
index 4d4551e..a148634 100644
--- a/llvm/docs/TableGen/LangIntro.rst
+++ b/llvm/docs/TableGen/LangIntro.rst
@@ -7,7 +7,7 @@
 
 .. warning::
    This document is extremely rough. If you find something lacking, please
-   fix it, file a documentation bug, or ask about it on llvmdev.
+   fix it, file a documentation bug, or ask about it on llvm-dev.
 
 Introduction
 ============