Internals: Rename Ast on non-node classes (#3262). No functional change.

This commit has the following replacements applied:

	s/\bAstUserInUseBase\b/VNUserInUseBase/g;
        s/\bAstAttrType\b/VAttrType/g;
        s/\bAstBasicDTypeKwd\b/VBasicDTypeKwd/g;
        s/\bAstDisplayType\b/VDisplayType/g;
        s/\bAstNDeleter\b/VNDeleter/g;
        s/\bAstNRelinker\b/VNRelinker/g;
        s/\bAstNVisitor\b/VNVisitor/g;
        s/\bAstPragmaType\b/VPragmaType/g;
        s/\bAstType\b/VNType/g;
        s/\bAstUser1InUse\b/VNUser1InUse/g;
        s/\bAstUser2InUse\b/VNUser2InUse/g;
        s/\bAstUser3InUse\b/VNUser3InUse/g;
        s/\bAstUser4InUse\b/VNUser4InUse/g;
        s/\bAstUser5InUse\b/VNUser5InUse/g;
        s/\bAstVarType\b/VVarType/g;

src/V3Active.cpp

@@ -199,7 +199,7 @@ public:
 //######################################################################
 // Collect existing active names
 
-class ActiveBaseVisitor VL_NOT_FINAL : public AstNVisitor {
+class ActiveBaseVisitor VL_NOT_FINAL : public VNVisitor {
 protected:
     VL_DEBUG_FUNC;  // Declare debug()
 };
@@ -299,7 +299,7 @@ private:
     // NODE STATE
     // Input:
     //  AstVar::user1p // V2LatchGraphVertex* The vertex handling this node
-    const AstUser1InUse m_inuser1;
+    const VNUser1InUse m_inuser1;
     // STATE
     LatchDetectGraph m_graph;  // Graph used to detect latches in combo always
     // VISITORS