array_unshift page, add an example with two associative arrays

[tiffany-taylor]

Added an example that shows how two associative arrays are combined using array_unshift()

https://www.php.net/manual/en/function.array-unshift.php

[tiffany-taylor]

~~Gah, need to fix the spacing on <![CDATA[, didn't mean to alter that.~~ Fixed.

[tiffany-taylor]

Converting this to draft so that I can provide a better example.

[cmb69]

I suggest not to think of "multi-dimensional" arrays in PHP; that eases the understanding how these are handled by language constructs and functions.

That said, I'm not against adding such an example for array_unshift(), since almost everybody talks about "multi-dimensional" PHP arrays.

[tiffany-taylor]

TFW I realize I meant to call it "associative" and not "multi-dimensional" 😆

[tiffany-taylor]

check-whitespace fails on a line that I fixed in the latest commit. It appears the job is looking at an older commit where the trailing whitespace was present. I'm not sure if the current failed job is a false-positive, or something I need to resolve.

[cmb69]

@tiffany-taylor, to make the white-space-checker happy, you need to squash the commits, and force-push.