Add callback freeing

[theVerySharpFlat]

Description

Running an LWJGL application using the debug library indicated that the GLFW callbacks were not being freed on window destruction, and as a result, memory was leaked. To fix this, I went in and added function calls to the destructors of the callbacks where necessary.

Type of change

• [X] Minor changes or tweaks (quality of life stuff)
• [X] 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 not work as expected)
• [ ] This change requires a documentation update

[theVerySharpFlat]

I fixed a format issue. Sorry about that!