impl NSTextInputClient

[Hperigo]

the PR implements the NSTextInputClient ( #460 ) for MTKView and NSOpenGLView, this will allow _sapp_macos_app to receive key code for characters like á, é, í, ó, ú

a couple of notes:

1. the _sapp.event.char_code is set inside insertText method. _sapp.event.modifiers and _sapp.event.key_repeat are still inside keyDown I'm not sure if this is going to break something, but it looks correct.
2. As suggested in the original feature request ( [Feature Request] - Support accented characters (non-us keyboard) on MacOS and Linux #460 ) this impl. is similar to the GLFW, the main difference is that firstRectForCharacterRange is returning return NSMakeRect(0.0, 0.0, 0.0, 0.0);. the original impl uses the window bounds, I'm not sure what is the difference here..

This is my first PR here, so feel free to point any corrections, etc.. =)

[floooh]

I need to read up on the macOS APIs to provide better feedback, but one dangerous thing I noticed while looking through the changes is that your PR undoes the following bug fix:

b326f33

Not sure how this can happen TBH.

[floooh]

(I changed the PR to a draft so that I don't accidentally click the merge button)

[Hperigo]

I'll double check the b326f33 that you pointed, I think that's was a mistake on my end..

please feel free to provide any other feedback =)

[eduardodoria]

I changed #460 because it is not working on Linux (Ubuntu 20.04.3 LTS) too.