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.

[TobiasBg]

Fix balanceTags() docs and make the function better readable

[SergeyBiryukov]

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.

[SergeyBiryukov]

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

[SergeyBiryukov]

In 23368:

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