Fix bandit companion identity in a few places

[spikymoth]

I think the important changes are in src/script.js (they're easy to miss because you can't refer to $companionBandit directly).

Miscellaneous fixes and changes:

• Fixes some instances of 'Banit' (only affected the image icon).
• Tidies up some identity checks to check for $companionBandit directly.
• Fixes (?) skewed and steady shrine to set correct name before capturing variable. Not sure this matters.
• Uses Array.prototype.findIndex in a few places instead of looping.