[clang-tidy] Widen anonymous namespace.

The matchers in this check are prone to create ODR violations otherwise.
No functionality change.

llvm-svn: 324083
diff --git a/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp b/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp
index ea3c33a..e259b6b 100644
--- a/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/RedundantExpressionCheck.cpp
@@ -32,10 +32,8 @@
 namespace clang {
 namespace tidy {
 namespace misc {
-
 namespace {
 using llvm::APSInt;
-} // namespace
 
 static constexpr llvm::StringLiteral KnownBannedMacroNames[] = {
     "EAGAIN",
@@ -629,6 +627,7 @@
 
   return LhsLoc.isMacroID() != RhsLoc.isMacroID();
 }
+} // namespace
 
 void RedundantExpressionCheck::registerMatchers(MatchFinder *Finder) {
   const auto AnyLiteralExpr = ignoringParenImpCasts(