C++ namespace cleanup (except tests).

libsolidity/ast/ASTUtils.cpp

@@ -18,9 +18,7 @@
 #include <libsolidity/ast/AST.h>
 #include <libsolidity/ast/ASTUtils.h>
 
-namespace dev
-{
-namespace solidity
+namespace solidity::frontend
 {
 
 VariableDeclaration const* rootVariableDeclaration(VariableDeclaration const& _varDecl)
@@ -39,4 +37,3 @@ VariableDeclaration const* rootVariableDeclaration(VariableDeclaration const& _v
 }
 
 }
-}