Add count support for repeat_last_insert '.' and repeat_last_select <a-.>

[Delapouite]

No description provided.

[lenormf]

The repetition primitives already remember the count used during the last operation, allowing a count on those would not serve much purpose as they would only multiply the cached count.

[Delapouite]

You're right. The . already remembers the count used in the command it repeats as you asked in #1465

But it's not the case of <a-.>.
Currently: ]p and 3]p acts the same. With this PR you can do ]p, and then 3<a-.>.

Also, back to the ., it offers interesting perspective.
For example making markdown headers. I'm a the beginning on the line I want to turn in a h1 : I#<esc>. I jump to the line I want to turn in a h2: 2.. Here comes a h4: 4.…
So it's useful when you made a command with 1 count and want to repeat a various count times depending of the context.

Finally, multiplying the command count with the repeating_last_insert count could lead to powerful edit operations in its own way.

[lenormf]

OK.

Currently: ]p and 3]p acts the same. With this PR you can do ]p, and then 3<a-.>.

As much as I understand the example, this would only be fixing a symptom, and not the root problem (which is that object selection doesn't support counts). Could be interesting in the mean time though.

Finally, multiplying the command count with the repeating_last_insert count could lead to powerful edit operations in its own way.

Such as? The current idiomatic way of repeating actions a fixed amount of times is through macros, which support counts already, do you have an example in mind?

[JJK96]

I second this, It happens quite often that I do an insert and want to repeat it a couple of times, so a count would be nice.

[JJK96]

@mawww Any reasons to not merge this change?