In documentation, replace references to 'list' with 'array'

[johannadevos]

In ticket #39049, a patch was submitted to replace the word 'list' with 'array' in one function.

On that ticket, there was a comment saying that "the terms array and list are often used interchangeably in documentation throughout WordPress core. In fact, searching for "a list of" in core returns almost 150 results."

For this ticket, replace all occurrences of 'list' in function documentation with 'array'.

[SergeyBiryukov]

In 49595:

Docs: Clarify that get_pages() returns an array of pages, not an HTML list.

Props ben.meredith@…, ovenall, johannadevos.
Fixes #39049. See #51768.