Fix saved file from new empty doc keeping created time tip issue

Fix https://community.notepad-plus-plus.org/topic/26235/notepad-v8-7-1-release-candidate/11?_=1730165549940

PowerEditor/src/NppIO.cpp

@@ -1651,7 +1651,10 @@ bool Notepad_plus::fileSave(BufferID id)
 	{
 		if (buf->isUntitled())
 		{
-			return fileSaveAs(bufferID);
+			bool isOK = fileSaveAs(bufferID);
+			if (isOK)
+				buf->clearTabCreatedTimeString();
+			return isOK;
 		}
 
 		const NppGUI & nppgui = (NppParameters::getInstance()).getNppGUI();

PowerEditor/src/ScintillaComponent/Buffer.h

@@ -292,6 +292,12 @@ public:
 			_tabCreatedTimeString = getTimeString(now);
 		}
 	}
+	void clearTabCreatedTimeString() {
+		if (_currentStatus != DOC_UNNAMED)
+		{
+			_tabCreatedTimeString = L"";
+		}
+	}
 
 	size_t docLength() const {
 		assert(_pManager != nullptr);