Condense namespaces in tint/resolver.

This PR condenses the namespaces in the tint/resolver folder.

Change-Id: I7ed4d677a3d1dd39a672fc2d4e6721a6a4f6157d
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/86031
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>
Auto-Submit: Dan Sinclair <dsinclair@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
diff --git a/src/tint/resolver/dependency_graph.cc b/src/tint/resolver/dependency_graph.cc
index be83f73..fd71ebe 100644
--- a/src/tint/resolver/dependency_graph.cc
+++ b/src/tint/resolver/dependency_graph.cc
@@ -32,8 +32,7 @@
 
 #define TINT_DUMP_DEPENDENCY_GRAPH 0
 
-namespace tint {
-namespace resolver {
+namespace tint::resolver {
 namespace {
 
 // Forward declaration
@@ -738,5 +737,4 @@
   return da.Run(module);
 }
 
-}  // namespace resolver
-}  // namespace tint
+}  // namespace tint::resolver