formula: rename installed_prefix and opt_or_installed_prefix_keg

[SeekingMeaning]

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The names installed_prefix and installed_version are misnomers as installed_prefix returns the prefix for the latest version of the formula, regardless of what versions may already be installed.

Proposed renames:
installed_prefix → latest_installed_prefix
opt_or_installed_prefix_keg → any_installed_keg

[Bo98]

The old names will need to be kept as aliases (for eventual deprecation) in compat.

[MikeMcQuaid]

Good idea, thanks for this @SeekingMeaning!

[MikeMcQuaid]

Hmm, not huge on this name but can't think of anything better.

[SeekingMeaning]

Question: When would this method be preferred over using latest_version_installed? and/or opt_or_installed_prefix_keg?

[MikeMcQuaid]

When you specifically want it to fail/return nil if it's an outdated version. If there's minimal/no usage: it could be removed entirely.

[SeekingMeaning]

Once #8548 and Homebrew/homebrew-core#59988 are merged, brew and homebrew-core shouldn't be using installed_version anymore but it's possible that it's used in other taps

[MikeMcQuaid]

In that case I reckon keep this name as-is and deprecate it so we can remove it eventually instead.

[SeekingMeaning]

Currently depends on #8432

[MikeMcQuaid]

This is a nice cleanup. Let's roll #8432 into here so they can be compared/combined. Would be good to audit the existing latest_, any_, installed_ prefix methods and replace all installed_ with a latest_ or any_ variant depending on what they handle.

[MikeMcQuaid]

In that case I reckon keep this name as-is and deprecate it so we can remove it eventually instead.

[MikeMcQuaid]

Fantastic work here, thanks @SeekingMeaning!