ast: Rename UnaryOp::kDereference to kIndirection

This is what it is (currently) called in the spec

Bug: tint:727
Change-Id: Ie24f42499ed20c0c45ef4e9474bc6bb6a19bfa36
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/51181
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: David Neto <dneto@google.com>
diff --git a/src/writer/wgsl/generator_impl.cc b/src/writer/wgsl/generator_impl.cc
index 7317829..a9607b2 100644
--- a/src/writer/wgsl/generator_impl.cc
+++ b/src/writer/wgsl/generator_impl.cc
@@ -709,12 +709,12 @@
 
 bool GeneratorImpl::EmitUnaryOp(ast::UnaryOpExpression* expr) {
   switch (expr->op()) {
-    case ast::UnaryOp::kDereference:
-      out_ << "*";
-      break;
     case ast::UnaryOp::kAddressOf:
       out_ << "&";
       break;
+    case ast::UnaryOp::kIndirection:
+      out_ << "*";
+      break;
     case ast::UnaryOp::kNot:
       out_ << "!";
       break;