Motivation / Problem

Use of the restart console command and network auto-restarting (NetworkCheckRestartMap) after opening the save/load window triggers an assertion failure.

Example reproduction steps:

1. Start a new game
2. Open the load game window (but don't actually load anything)
3. Run restart in the console

Description

ShowSaveLoadDialog incorrectly overwrites the value of _file_to_saveload.abstract_ftype.
This value is used by the restart console command and by NetworkCheckRestartMap.

The value of the _file_to_saveload.abstract_ftype must be consistent with the other members of _file_to_saveload.

Limitations

N/A

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, gs_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • PR must be added to API tracker