Implement "--log" option for commit window

This fixes a regression. The previous commit window allowed a "--log" option to be specified that would pre-populate the text view with the given argument.
fixup! Allow user to clear previous commit messages
Change to project folder when running commands from commit window
fixup! Add assertion about being called in the main dispatch queue
Remove unused include (cf/callback.h)
Run in default run-loop mode for document_t::sync_open
Add assertion to check if index is within allowed range
Add a ‘did change content’ notification to document_t

This is only meant for when the document reloads content because the file was changed on disk. Long-term though, I think reloading document because of disk changes should be handled at a higher level.
Give local function ‘static’ storage
Get rid of OakCreateViewWithColor
Do not render full screen windows as inactive

The text view itself will still dim the selection, but document tabs, status, and tool bars no longer change colors.

This seems consistent with how Apple’s controls act and is necessary for the status bar since it draws a transparent gradient over the window background, so only its borders got the dimmed look.