C++ namespace cleanup (except tests).

libsolidity/analysis/ControlFlowBuilder.h

@@ -24,8 +24,7 @@
 #include <array>
 #include <memory>
 
-namespace dev {
-namespace solidity {
+namespace solidity::frontend {
 
 /** Helper class that builds the control flow of a function or modifier.
  * Modifiers are not yet applied to the functions. This is done in a second
@@ -161,4 +160,3 @@ private:
 };
 
 }
-}