"Allow guessing anywhere" help text is somewhat inacurate

[meeque]

Currently the help text says:

By default, you are allowed to guess only on the boundary of revealed tiles.

There are some situations when revealing outside tiles seems allowed, regardless of ticking this checkbox:

1. When an outside tile is guaranteed not to contain a mine, see issue Outside as safe cells #13 for examples.
2. When all tiles on the boundary are guaranteed to contain a mine.

Example for the latter in a 3*2 game:

+-+-+-+
|2|x| |
+-+-+-+
|2|x| |
+-+-+-+

Here, all boundary tiles contain mines, so the game allows safely revealing either of the remaining tiles. Not sure how to rephrase the help text without getting too confusing. Maybe something like:

By default, you are allowed to guess only on the boundary of revealed tiles, unless forced otherwise.

[837951602]

When outside is safe then it isn't a "guess". "unless forced otherwise" is good.
p.s. the init state can be treated as a special case of "all boundary is deadly"