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/V3InstrCount.cpp

@@ -29,12 +29,12 @@
 /// we'll count instructions from either the 'if' or the 'else' branch,
 /// whichever is larger. We know we won't run both.
 
-class InstrCountVisitor final : public AstNVisitor {
+class InstrCountVisitor final : public VNVisitor {
 private:
     // NODE STATE
     //  AstNode::user4()        -> int.  Path cost + 1, 0 means don't dump
     //  AstNode::user5()        -> bool. Processed if assertNoDups
-    const AstUser4InUse m_inuser4;
+    const VNUser4InUse m_inuser4;
 
     // MEMBERS
     uint32_t m_instrCount = 0;  // Running count of instructions
@@ -258,7 +258,7 @@ private:
 };
 
 // Iterate the graph printing the critical path marked by previous visitation
-class InstrCountDumpVisitor final : public AstNVisitor {
+class InstrCountDumpVisitor final : public VNVisitor {
 private:
     // NODE STATE
     //  AstNode::user4()        -> int.  Path cost, 0 means don't dump