Specify units on all flags and config settings

[josebolos]

A source of errors that may be relatively common but hard to debug is assuming the (wrong) units for a specific input. For example, the timeout value in pa11y is specified in milliseconds, but people more familiar with other programming languages may assume that the timeout is specified in, say, seconds instead.

These errors may be tricky to debug, specially if they are related to time units.

I propose we modify all settings and config items so the units are always part of the name of the setting, configuration option, or function input.

The way forward would probably be something like:

• Add the new settings/options as an alternative/alias to the existing one (Current MAJOR version)
• Mark the unit-less options as deprecated (Version MAJOR + 1)
• Remove the unit-less options (Version MAJOR + 2)

A nice reference, with examples of the problems and ways around it:
https://ruudvanasseldonk.com/2022/03/20/please-put-units-in-names

An alternative for functions (we may not need this in this case):
https://afontcu.medium.com/cool-javascript-9-named-arguments-functions-that-get-and-return-objects-337b6f8cfa07