Make -no-hooks default with execute-keys and evaluate-commands

[danr]

This is a follow-up on #1692 where it was identified that hooks enabled being the default on exec and eval is a surprising default. Personally I typically add -no-hooks as often as I can remember to exec and eval and I can count without using any hands when I actually wanted to have them on.

This issue suggests that hooks should be off by default. They could be enabled with a -with-hooks flag.

[mawww]

Yeah, I think such a change would make sense, but we need to experiment with it to see what it breaks.

[lenormf]

Related #707.

[h-youhei]

How about hook -with-commands or hook -with-keys instead of eval -with-hooks.

I think it makes easy to handle side effect.

[mawww]

I have been experimenting with this, and it is not as good as expected.

It seems the root of the problem is that we try to treat eval and exec the same way. But typically, we want hooks active in most eval, in particular any edit command should run with hooks, except when we are sure we do not want hooks to run. exec are often not expected to trigger hooks.

Also, some hooks really want to always run, such as the ones taking care of removing temporary folders when a fifo is closed. We do not want to leave temporary directories because a fifo was closed during a non-hooked eval. This is why the hook command gained a -always switch.

Finally, the initial issue would now be fixed because faces, and hence colorschemes, are now scoped, meaning those hooks would be less likely to interfere.

All that to say, I am still unsure what the best solution would be, but while disabling hooks by default felt like a nice idea, it proved to be unsufficient.