Remember last-used string in the Find dialog in conhost (#2845)

(cherry picked from commit bfb1484)

src/interactivity/win32/find.cpp

@@ -23,13 +23,16 @@ INT_PTR CALLBACK FindDialogProc(HWND hWnd, UINT Message, WPARAM wParam, LPARAM l
     // This bool is used to track which option - up or down - was used to perform the last search. That way, the next time the
     //   find dialog is opened, it will default to the last used option.
     static bool fFindSearchUp = true;
+    static std::wstring lastFindString;
+
     WCHAR szBuf[SEARCH_STRING_LENGTH + 1];
     switch (Message)
     {
     case WM_INITDIALOG:
         SetWindowLongPtrW(hWnd, DWLP_USER, lParam);
         SendDlgItemMessageW(hWnd, ID_CONSOLE_FINDSTR, EM_LIMITTEXT, ARRAYSIZE(szBuf) - 1, 0);
         CheckRadioButton(hWnd, ID_CONSOLE_FINDUP, ID_CONSOLE_FINDDOWN, (fFindSearchUp ? ID_CONSOLE_FINDUP : ID_CONSOLE_FINDDOWN));
+        SetDlgItemText(hWnd, ID_CONSOLE_FINDSTR, lastFindString.c_str());
         return TRUE;
     case WM_COMMAND:
     {
@@ -40,6 +43,7 @@ INT_PTR CALLBACK FindDialogProc(HWND hWnd, UINT Message, WPARAM wParam, LPARAM l
             USHORT const StringLength = (USHORT)GetDlgItemTextW(hWnd, ID_CONSOLE_FINDSTR, szBuf, ARRAYSIZE(szBuf));
             if (StringLength == 0)
             {
+                lastFindString.clear();
                 break;
             }
             bool const IgnoreCase = IsDlgButtonChecked(hWnd, ID_CONSOLE_FINDCASE) == 0;
@@ -48,7 +52,7 @@ INT_PTR CALLBACK FindDialogProc(HWND hWnd, UINT Message, WPARAM wParam, LPARAM l
             SCREEN_INFORMATION& ScreenInfo = gci.GetActiveOutputBuffer();
 
             std::wstring wstr(szBuf, StringLength);
-
+            lastFindString = wstr;
             LockConsole();
             auto Unlock = wil::scope_exit([&] { UnlockConsole(); });