doc: relax prohibition on personal pronouns

Our personal pronoun prohibition is contrary to most current technical
documentation style guides. The prohibition on personal pronouns comes
from academic style guides. It results in an unnecessary formal tone. It
encourages wordiness and the overuse of passive voice.

This change to our style guide more closely aligns us with the style
guides of companies like Google, IBM, and  Microsoft.

Google's style guide suggests avoiding first-person pronouns and
suggests: "Use the second-person pronoun (_you_) whenever possible."
Refs: https://developers.google.com/style/pronouns#personal-pronouns

IBM's style guide also recommends second-person voice ("Use second
person ('you')").
Refs: https://www.ibm.com/developerworks/library/styleguidelines/index.html

Similarly, Microsoft's style guide recommends using first person
sparingly and avoiding first-person plural. "In general, use second
person".
Refs: https://docs.microsoft.com/en-us/style-guide/grammar/person#in-general-use-second-person

PR-URL: https://github.com/nodejs/node/pull/34353


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Mary Marchini <oss@mmarchini.me>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>