Compilation feature for alt-display by default

I find the default `fmt::Display` implementation not very useful and kinda always want the `#`-based alt display. For me, the power of the `.context("...")` pattern is that it **adds** context to the error, but if you don't use the alt-display, you're actually just replacing the error message, not adding anything.

Would this project accept a patch that adds an optional feature flag (`alt-display` or so) that makes that the default display method?

(I would personally go as far as arguing that the alt should be the default.)

The issue names no files, tests, or entry points. Start by locating the existing Display formatting behavior and its tests, then determine how an optional alt-display feature would affect the default output. Done means the feature's scope and expected formatting are specified and verified without changing the existing behavior when it is disabled.

Written by the indexing model from the issue text.