Feature request: Provide customary RFC 3986 encoding

[daniel-pfeiffer]

• Note that this crate implements the URL Standard not RFC 1738 or RFC 3986

Note taken, but why? RFC 3986 (or even wider open) is the standard everybody follows for URLs. While Chrome and FF are represented in that WG, they do not follow this nonsense in their encodeURIComponent().

And it makes a huge difference for human readability! It would cost you nothing to add one with these 4 harmless characters:

const RESERVED/*_RFC_3986*/: &AsciiSet = &NON_ALPHANUMERIC
    .remove(b'-')
    .remove(b'.')
    .remove(b'_')
    .remove(b'~');

Or the other way round, adding to CONTROLS, and then NON_ALPHANUMERIC to this one.