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/V3Descope.cpp

@@ -34,12 +34,12 @@
 
 //######################################################################
 
-class DescopeVisitor final : public AstNVisitor {
+class DescopeVisitor final : public VNVisitor {
 private:
     // NODE STATE
     //  Cleared entire netlist
     //   AstCFunc::user()               // bool.  Indicates processing completed
-    const AstUser1InUse m_inuser1;
+    const VNUser1InUse m_inuser1;
 
     // TYPES
     using FuncMmap = std::multimap<std::string, AstCFunc*>;
@@ -168,7 +168,7 @@ private:
                 // Not really any way the user could do this, and we'd need
                 // to come up with some return value
                 // newfuncp->addStmtsp(new AstDisplay(newfuncp->fileline(),
-                //                                   AstDisplayType::DT_WARNING,
+                //                                   VDisplayType::DT_WARNING,
                 //                                   string("%%Error: ")+name+"() called with bad
                 //                                   scope", nullptr));
                 // newfuncp->addStmtsp(new AstStop(newfuncp->fileline()));