docs: Add link to HowToSetUpLLVMStyleRTTI

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168271 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/CodingStandards.rst b/docs/CodingStandards.rst
index 9083530..c89a30d 100644
--- a/docs/CodingStandards.rst
+++ b/docs/CodingStandards.rst
@@ -409,7 +409,8 @@
 
 That said, LLVM does make extensive use of a hand-rolled form of RTTI that use
 templates like `isa<>, cast<>, and dyn_cast<> <ProgrammersManual.html#isa>`_.
-This form of RTTI is opt-in and can be added to any class.  It is also
+This form of RTTI is opt-in and can be
+:doc:`added to any class <HowToSetUpLLVMStyleRTTI>`. It is also
 substantially more efficient than ``dynamic_cast<>``.
 
 .. _static constructor: