Add support for formatting boolean values in WP_CLI\Formatter

[tfirdaus]

This Pull Request aims to fix issue #5542, where a false value is currently transformed into an empty string.

+----+--------+
| id | status |
+----+--------+
| 1  | 1      |
| 2  |        |
+----+--------+

With these updates, the output for boolean values will be transformed into true and false accordingly.

+----+--------+
| id | status |
+----+--------+
| 1  | true   |
| 2  | false  |
+----+--------+

[swissspidy]

Nice!

[swissspidy]

It's hack day, so let's 🚢 it!

#5935

[danielbachhuber]

Thanks for the PR, @tfirdaus !

We decided to revert this for now in #5940 because:

1. It's technically a breaking change.
2. I'm concerned it will unexpectedly break folks' scripts that are parsing tabular output.

I filed #5542 against the 3.0 milestone. We can re-open this PR when 3.0 is the next slated release.

[tfirdaus]

@danielbachhuber No worries. Thanks for your help.