Fix accordion and tab targets with special meaning characters

[jaskorpe]

This fixes the issue of special meaning characters in id's on togglable tabs, and collapsible panels without the need for escaping the id's.

Refs: #14285, #13832

[cvrebert]

• There are some additional places that would also need to be changed: see Escape selectors #13832 (comment)
• There are possibly performance concerns with this approach. Do browsers optimize id attribute selectors like they do #id selectors? Does it take jQuery longer to parse these attribute selectors?
• The Travis build is failing due to some apparent breakage in the unit tests
• New unit tests should be added to specifically test the handling of "exotic" IDs

[hnrch02]

Does it take jQuery longer to parse these attribute selectors?

Not sure about parsing but Sizzle uses the much faster getElementById when # is matched, see https://github.com/jquery/sizzle/blob/9bf8ecbc8d39e436cdedd23be5f1843e2587c507/src/sizzle.js#L208.

Anyways, as I said in #13832 (comment), support for these "exotic" IDs is planned for v4 so I'd rather not go this route for v3.

[jaskorpe]

I did see that you wanted to wait, but I didn't see any mention of attribute selectors in the proposed patch. If there indeed is a performance penalty, I agree that it is best not to merge these patches.

The patches also introduces some uncertainty in the api since the documentation suggests using # as href value, and then allowing the id to start with a hash.

[hnrch02]

I will close this as we're unlikely to add support for this in v3.
As I said, support for these IDs is planned for v4 when we'll hopefully have a better infrastructure for common utilities across the plugins, so you just have to use normal IDs until then. Thanks for the work though!

[ktmud]

Another weird case is IDs with a colon. For example, Hugo will generate section anchors with IDs like #SOME_TITLE:13f5f3bf.

While this is a valid "href" attribute for an anchor, passing it to jQuery directly will not find the element. However, $("#SOME_TITLE\\:13f5f3bf") will work.