Guts of a text editor for games etc., implementing them from scratch
Description
This C header file implements the guts of a multi-line text-editing widget; you
implement display, word-wrapping, and low-level string insertion/deletion, and
stb_textedit will map user inputs into insertions & deletions, plus updates to
the cursor position, selection state, and undo state.
It is intended for use in games and other systems that need to build their own
custom widgets and which do not have heavy text-editing requirements (this
library is not recommended for use for editing large texts, as its performance
does not scale and it has limited undo).
Non-trivial behaviors are modeled after Windows text controls.
