doc: normalize shell code block info strings

Prior to this commit, shell fenced code blocks in Markdown files had
inconsistent info strings. This has been corrected to standarize on
the one with the highest frequency in the doc/api/ dir.

Stats:
> 'console' => 54,
> 'shell' => 2,

PR-URL: https://github.com/nodejs/node/pull/33486


Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>