"Save and Quit to Title" button in the "Note about custom screens" screen needs its own string

The “Save and Quit to Title” button on the “Note about custom screens” screen uses the same string as the "Save and Quit to Title" button in the Pause menu (menu.returnToMenu), which causes issues in some languages where the text doesn't fit due to the smaller width in the aforementioned screen.

Steps to reproduce the issue

1. If not already done, set the current language to “English (US)”.

2. Run the command dialog show @a minecraft:custom_options.

3. Click the ⚠️ button to open the info screen.

4. Verify that the text fits inside the button to the left.

5. Change in-game language to any of the following affected languages*:

   1. Deutsch (Deutschland)

   2. Français (France)

   3. Italiano (Italia)

   4. Lëtzebuergesch (Lëtzebuerg)

   5. Nederlands (Nederland)

6. Run the same command from step 2.

7. The text does not longer fit inside the same button from step 3.

^{*: Many other languages are also affected!}

Expected result:

To ensure the “Save and Quit to Title” button on the new “Note about custom screens” screen fits properly in all languages, a separate string should be added. This would align with the approach taken for other settings, where separate strings are used for different elements (for example options.sounds and options.sounds.title).

Actual result:

The current string used for the “Save and Quit to Title” button on the “Note about custom screens” screen is the same as for the “Save and Quit to Title” button in the Pause menu.

See the attached examples, which illustrate this need for a separate string.