More readable regular expressions for Press This URL's

[dd32]

The regular expressions in Press This are hard to read.
The attached patch does (probably among other things)

• Switches to using ! instead of / as the delimiter, so that / doesn't need escaping inline
• Removes the escaping of ? and . within character maps [.?] as they don't need escaping there
• Adds case-insensitive matching to most expressions, aside from /wp-includes/
• Removes the usage of {1} as a single-character match is implied
• Not certain what preg_match( '/\/ad[sx]{1}?\//', $src ) was supposed to match (/ad/, /ads/, and /adx/? If so, it's not currently matching /ad/, which this patch changes)

The patch is untested so far, needs to be reviewed to check I didn't miss anything.

[azaozz]

The patch looks good. We can also make pretty much all groups non-capturing as they are only used to check if matches exist.

We can probably combine !/([^./]+[-_])?(spinner|loading|spacer|blank)s?([-_][^./]+)?\.[a-z0-9]{3,4}!i and !/(spinner|loading|spacer|blank|rss)\.(gif|jpg|png)!i, as they are pretty close (assuming \.[a-z0-9]{3,4} is to match image extensions).

[kraftbj]

@azaozz @dd32 - Any other thoughts on this? Anything in particular I can help test that you're more worried about?

[dd32]

In 34736:

Press This: Make the regular expressions for matching images easier to read by not requiring escaping.
Fixes #32878