Fix formatting of some comments (NFC) (#2091)

A few things that were missing in #2048.

Author: aheejin

src/wasm-traversal.h

@@ -704,8 +704,8 @@ struct Walker : public VisitorType {
   void setFunction(Function* func) { currFunction = func; }
 
 private:
-  Expression** replacep =
-    nullptr; // the address of the current node, used to replace it
+  // the address of the current node, used to replace it
+  Expression** replacep = nullptr;
   SmallVector<Task, 10> stack;      // stack of tasks
   Function* currFunction = nullptr; // current function being processed
   Module* currModule = nullptr;     // current module being processed

src/wasm-type.h

@@ -28,9 +28,10 @@ enum Type {
   f32,
   f64,
   v128,
-  unreachable // none means no type, e.g. a block can have no return type. but
-              // unreachable is different, as it can be "ignored" when doing
-              // type checking across branches
+  // none means no type, e.g. a block can have no return type. but unreachable
+  // is different, as it can be "ignored" when doing type checking across
+  // branches
+  unreachable
 };
 
 const char* printType(Type type);