Improve usability of create game form

[garrettngarcia]

Fixes #11071

Before clicking "Create"

• Branch is derived from the latest master
• Add the pins or archive_alpha_games label if this change will break existing games
• Code passes linter with docker compose exec rack rubocop -a
• Tests pass cleanly with docker compose exec rack rake

Implementation Notes

Explanation of Change

Now selects number input field value on focus. Also added min and max player info to the form labels.

Tested on Safari and Chrome on iOS and Mac.

Screenshots

Any Assumptions / Hacks

[ollybh]

@garrettngarcia Thanks for looking into this highly annoying bug. However, I don't think that this is the correct way to fix this one.

The problem, as far as I understand it, is that we've got some over-zealous validation code. If you delete the player count from one of the boxes it sees the blank as zero, which is less than the minimum player could. So it helpfully re-populates the box with the minimum player count.

This needs to be redone so that the blank doesn't trigger adding the minimum player count. And we'd probably need to make sure that the form isn't submitted with an invalid player count – I think this validation code was added to prevent games being created with invalid counts.