Fix balanceTags() docs and make the logic better readable

[TobiasBg]

The inline documentation of balanceTags() mixes up "and" and "or" in the first line. The function will does not require both $force and get_option(...) to be true, but just one. Apparently, some of the inline docs was already worked on in #19576, but the first line was left as-is.
Also, the logic of the function is kind of hard to read with unnecessary boolean inversions.

The attached patch fixed the docs and makes the function better readable.

Fix balanceTags() docs and make the function better readable

Boolean inversions are the result of the changes [3751] and [5805].

The initial description (that appears to be inaccurate) was added in [8783].

22537-balanceTags.patch​ looks good.

Also passes the unit tests in formatting/balanceTags.php and post/filtering.php.

In 23368:

Correct the documentation for balanceTags(). Remove unnecessary boolean inversion. props TobiasBg. fixes #22537.