[include-cleaner] Treat a constructor call as a use of the class type.

[hokein]

Summary

Per the discussion in https://github.com/llvm/llvm-project/issues/59916.

clang-tools-extra/include-cleaner/lib/WalkAST.cpp

public:
   }
   bool VisitCXXDependentScopeMemberExpr(CXXDependentScopeMemberExpr *E) {
     report(E->getMemberLoc(), getMemberProvider(E->getBaseType()),
            RefType::Implicit);
     return true;
   }
 
   bool VisitCXXConstructExpr(CXXConstructExpr *E) {
-    report(E->getLocation(), E->getConstructor(),
+    report(E->getLocation(), getMemberProvider(E->getType()),
            E->getParenOrBraceRange().isValid() ? RefType::Explicit
                                                : RefType::Implicit);
     return true;
   }
 
   bool VisitOverloadExpr(OverloadExpr *E) {
     // Since we can't prove which overloads are used, report all of them.
     llvm::for_each(E->decls(), [this, E](NamedDecl *D) {

clang-tools-extra/include-cleaner/unittests/WalkASTTest.cpp

TEST(WalkAST, MemberExprs) {
   testWalk("template<typename T> struct $implicit^Base { void method(); };",
            "template<typename T> void k(Base<T>& t) { t.^method(); }");
   testWalk("template<typename T> struct $implicit^Base { void method(); };",
            "template<typename T> void k(Base<T>* t) { t->^method(); }");
 }
 
 TEST(WalkAST, ConstructExprs) {
   testWalk("struct $implicit^S {};", "S ^t;");
-  testWalk("struct S { $implicit^S(); };", "S ^t;");
-  testWalk("struct S { $explicit^S(int); };", "S ^t(42);");
-  testWalk("struct S { $implicit^S(int); };", "S t = ^42;");
+  testWalk("struct $implicit^S { S(); };", "S ^t;");
+  testWalk("struct $explicit^S { S(int); };", "S ^t(42);");
+  testWalk("struct $implicit^S { S(int); };", "S t = ^42;");
+  testWalk("namespace ns { struct S{}; } using ns::$implicit^S;", "S ^t;");
 }
 
 TEST(WalkAST, Operator) {
   // References to operators are not counted as uses.
   testWalk("struct string {}; int operator+(string, string);",
            "int k = string() ^+ string();");
   testWalk("struct string {int operator+(string); }; ",
            "int k = string() ^+ string();");