edit: Move most code from `edit()` to `insert_{enter,check,execute}`

Refactor insert mode to use `state_enter` as an event loop:

- Move o_lnum(static variable) outside function
- Move code before the insert mode loop into `insert_enter`
- Move code before `safe_vgetc()` call into `insert_check`
- Move code after `safe_vgetc()` call into `insert_execute`
- Remove doESCkey label and handle insert mode repeating in the `insert_enter`
  function
- Remove do_intr label(this is not the place for platform-specific interrupt
  charts)

0 files changed, 0 insertions, 0 deletions