Docs: Typo correction in class-wpdb.php

[truptikanzariya]

There is a typo correction in the following file:

src/wp-includes/class-wpdb.php

This patch fixes minor documentation typos and improves comment clarity within the file.

The change enhances accuracy and ensures consistency with the correct spelling used elsewhere in the WordPress codebase.

[rollybueno]

This looks more like coding standard rather than typo.

[westonruter]

In 61102:

Coding Standards: Improve formatting of phpdoc for params in wpdb class.

Props truptikanzariya, rollybueno.
See #63168.
Fixes #64160.

[sabernhardt]

For history:

• [21512] added the __unset() method, and the parameter description already had the extra space before it (and lacked the period at the end).
• The alignment changes relate to [56476].