Shorten DiagnosticInfoOptimizationRemark* to OptimizationRemark*. NFC

With the new streaming interface, these class names need to be typed a
lot and it's way too looong.

llvm-svn: 282544
diff --git a/llvm/lib/Transforms/IPO/Inliner.cpp b/llvm/lib/Transforms/IPO/Inliner.cpp
index 89ae11c..3ffb754 100644
--- a/llvm/lib/Transforms/IPO/Inliner.cpp
+++ b/llvm/lib/Transforms/IPO/Inliner.cpp
@@ -470,8 +470,7 @@
         if (Function *Callee = CS.getCalledFunction())
           if (Callee->isDeclaration()) {
             using namespace ore;
-            ORE.emit(DiagnosticInfoOptimizationRemarkMissed(DEBUG_TYPE,
-                                                            "NoDefinition", &I)
+            ORE.emit(OptimizationRemarkMissed(DEBUG_TYPE, "NoDefinition", &I)
                      << NV("Callee", Callee) << " will not be inlined into "
                      << NV("Caller", CS.getCaller())
                      << " because its definition is unavailable"