Resolve two warnings related to doc comments.

Author: tshortli

clang/include/clang/Sema/CodeCompleteConsumer.h

@@ -335,7 +335,7 @@ class CodeCompletionContext {
     /// error and don't know which completions we should give.
     CCC_Recovery,
 
-    /// Code completion in a `@class` forward declaration.
+    /// Code completion in a \c \@class forward declaration.
     CCC_ObjCClassForwardDecl
   };
 

llvm/include/llvm/IR/DIBuilder.h

@@ -505,7 +505,7 @@ namespace llvm {
     /// \param UniqueIdentifier A unique identifier for the union.
     /// \param OffsetInBits The offset of the variant payload in the variant
     /// type.
-    /// \param SpareBitMask A mask of spare bits of the payload, spare bits are
+    /// \param SpareBitsMask A mask of spare bits of the payload, spare bits are
     /// bits that aren't used in any of the variant's cases.
     DICompositeType *
     createVariantPart(DIScope *Scope, StringRef Name, DIFile *File,