[WebAssembly] Add some comments and tidy up whitespace.

llvm-svn: 296402
diff --git a/llvm/lib/MC/WasmObjectWriter.cpp b/llvm/lib/MC/WasmObjectWriter.cpp
index 9c0a593..e61b125 100644
--- a/llvm/lib/MC/WasmObjectWriter.cpp
+++ b/llvm/lib/MC/WasmObjectWriter.cpp
@@ -283,7 +283,8 @@
 
 namespace {
 
-// 
+// The signature of a wasm function, in a struct capable of being used as a
+// DenseMap key.
 struct WasmFunctionType {
   // Support empty and tombstone instances, needed by DenseMap.
   enum { Plain, Empty, Tombstone } State;
@@ -356,7 +357,7 @@
   uint32_t InitialValue;
 };
 
-}  // end anonymous namespace
+} // end anonymous namespace
 
 // Write X as an (unsigned) LEB value at offset Offset in Stream, padded
 // to allow patching.