Renaming CERT documentation files to use the CERT rule identifiers. This is for consistency with other checkers, where the documentation file name matches the checker name. NFC of the checkers.

llvm-svn: 256474
diff --git a/clang-tools-extra/clang-tidy/cert/VariadicFunctionDefCheck.h b/clang-tools-extra/clang-tidy/cert/VariadicFunctionDefCheck.h
index 9ee8683..7463063 100644
--- a/clang-tools-extra/clang-tidy/cert/VariadicFunctionDefCheck.h
+++ b/clang-tools-extra/clang-tidy/cert/VariadicFunctionDefCheck.h
@@ -18,7 +18,7 @@
 /// Guards against any C-style variadic function definitions (not declarations).
 ///
 /// For the user-facing documentation see:
-/// http://clang.llvm.org/extra/clang-tidy/checks/cert-variadic-function-def.html
+/// http://clang.llvm.org/extra/clang-tidy/checks/cert-dcl50-cpp.html
 class VariadicFunctionDefCheck : public ClangTidyCheck {
 public:
   VariadicFunctionDefCheck(StringRef Name, ClangTidyContext *Context)