Description

UI: Use Qt::MiddleButton instead of deprecated Qt::MidButton

Motivation and Context

Qt::MidButton has been deprecated since Qt4 and removed in Qt6. It was replaced by Qt::MiddleButton, which is available in all versions of Qt5. Building against Qt 5.15+ will produce compiler warnings when using Qt::MidButton, and warnings are bad.

qt/qtbase@880cbf6
qt/qtbase@16e546e

How Has This Been Tested?

I compiled and ran OBS on Windows 10 Home 64-bit 2004 (Build 19041.630). I bound "Start Recording" to my mouse's middle button, and tested the hotkey, and it worked fine.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

• Code cleanup (non-breaking change which makes code smaller or more readable)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.