Multi-line text rendering should support custom line-height

[andrewhong04]

Multi-line text rendering should support custom line-height. Even though SDL2 does not support this natively (TTF_RenderUTF8_Blended_Wrapped). Sometimes when I use it, the line-height is way too high or too low to my liking.

[Starbuck5]

This would need to be added to SDL_ttf.

I opened an issue for line alignment and line height (libsdl-org/SDL_ttf#160), but I only handled line spacing and didn't protest when the issue was closed without line height being added.