Fix accented characters not found in "find in files" issues

Fix accented characters in ANSI files not found in "find in files" and "replace in files" commands issues.
This regression (in v7.7 from v7.6.6) is due to the upgrade of Scintilla from v3.56 to v4.14.

Fix #5825, fix #5830, fix #7668, fix #7773

PowerEditor/src/Notepad_plus.cpp

@@ -1749,8 +1749,14 @@ bool Notepad_plus::findInFiles()
 		{
 			Buffer * pBuf = MainFileManager.getBufferByID(id);
 			_invisibleEditView.execute(SCI_SETDOCPOINTER, 0, pBuf->getDocument());
-			auto cp = _invisibleEditView.execute(SCI_GETCODEPAGE);
+			auto detectedCp = _invisibleEditView.execute(SCI_GETCODEPAGE);
-			_invisibleEditView.execute(SCI_SETCODEPAGE, pBuf->getUnicodeMode() == uni8Bit ? cp : SC_CP_UTF8);
+			int cp2set = SC_CP_UTF8;
+			if (pBuf->getUnicodeMode() == uni8Bit)
+			{
+				cp2set = (detectedCp == SC_CP_UTF8 ? CP_ACP : detectedCp);
+			}
+
+			_invisibleEditView.execute(SCI_SETCODEPAGE, cp2set);
 			FindersInfo findersInfo;
 			findersInfo._pFileName = fileNames.at(i).c_str();
 			nbTotal += _findReplaceDlg.processAll(ProcessFindAll, FindReplaceDlg::_env, isEntireDoc, &findersInfo);