fix: Fix full-screen toggling repeatedly while holding Alt + Enter

[ClamEater14]

PR Details

This PR fixes the full-screen toggle being activated repeatedly while holding the Alt + Enter key combination. The fix involves checking if the key combination was not already held down by ensuring the previous key state flag (aka KF_REPEAT) in the LParam of the Windows message is 0.

With the fix applied, one can toggle full screen only by pressing Enter (down and up) while holding Alt.

See documentation on the WM_SYSKEYDOWN message (including the LParam details I mentioned) here: https://learn.microsoft.com/en-us/windows/win32/inputdev/wm-syskeydown#remarks

Related Issue

Fixes #1530

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My change requires a change to the documentation.
• I have added tests to cover my changes.
• All new and existing tests passed.
• I have built and run the editor to try this change out.

[ClamEater14]

@dotnet-policy-service agree

[Eideren]

Works great, thanks for looking into this one and sorry about the delay !