doc: do not use & for "and" in text

This also changes a line in the man page to be sentence case.

Refs: https://docs.microsoft.com/en-us/style-guide/a-z-word-list-term-collections/term-collections/special-characters

PR-URL: #39345
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

doc/guides/writing-tests.md

@@ -20,7 +20,7 @@ Add tests when:
 
 ## Test directory structure
 
-See [directory structure overview][] for outline of existing test & locations.
+See [directory structure overview][] for outline of existing test and locations.
 When deciding on whether to expand an existing test file or create a new one,
 consider going through the files related to the subsystem.
 For example, look for `test-streams` when writing a test for `lib/streams.js`.

doc/node.1

@@ -698,7 +698,7 @@ Documentation:
 .Sy https://nodejs.org/api/
 .
 .Pp
-GitHub repository & Issue Tracker:
+GitHub repository and issue tracker:
 .Sy https://github.com/nodejs/node
 .
 .Pp

onboarding.md

@@ -26,7 +26,7 @@ onboarding session.
 
 * This session will cover:
   * [local setup](#local-setup)
-  * [project goals & values](#project-goals--values)
+  * [project goals and values](#project-goals-and-values)
   * [managing the issue tracker](#managing-the-issue-tracker)
   * [reviewing PRs](#reviewing-prs)
   * [landing PRs](#landing-prs)
@@ -60,7 +60,7 @@ The project has two venues for real-time discussion:
 * [`#nodejs-dev`](https://openjs-foundation.slack.com/archives/C019Y2T6STH) on
   the [OpenJS Foundation](https://slack-invite.openjsf.org/)
 
-## Project goals & values
+## Project goals and values
 
 * Collaborators are the collective owners of the project
   * The project has the goals of its contributors