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/V3Life.cpp

@@ -41,7 +41,7 @@
 class LifeState final {
     // NODE STATE
     //   See below
-    const AstUser1InUse m_inuser1;
+    const VNUser1InUse m_inuser1;
 
     // STATE
 public:
@@ -267,7 +267,7 @@ public:
 //######################################################################
 // Life state, as a visitor of each AstNode
 
-class LifeVisitor final : public AstNVisitor {
+class LifeVisitor final : public VNVisitor {
 private:
     // STATE
     LifeState* const m_statep;  // Current state
@@ -449,7 +449,7 @@ public:
 
 //######################################################################
 
-class LifeTopVisitor final : public AstNVisitor {
+class LifeTopVisitor final : public VNVisitor {
     // Visit all top nodes searching for functions that are entry points we want to start
     // finding code within.
 private: