Explain differences when working in the website repository

[jdbaldry]

Taylor noticed that these instructions cause confusion when they are applied to the website repository.

This change seeks to clarify those slight differences without going too deep because the audience is primarily going to be working in project repositories.

[github-actions[bot]]

Readability report

File	AutomatedReadability	ColemanLiau	FleschKincaid	FleschReadingEase	GunningFog	LIX	SMOG
docs/sources/review/test-documentation-changes/index.md	$${7.00\space\color{green}(Δ-0.01)}$$	$${10.27\space\color{green}(Δ-0.05)}$$	$${8.61\space\color{green}(Δ-0.01)}$$	$${52.28\space\color{green}(Δ+0.31)}$$	$${10.57\space\color{red}(Δ+0.04)}$$	$${40.97\space\color{green}(Δ-0.13)}$$	$${11.21\space\color{red}(Δ+0.03)}$$
docs/sources/shared/make-help.md	$${8.45\space\color{red}(Δ+0.05)}$$	$${11.60\space\color{green}(Δ-0.13)}$$	$${11.07\space\color{red}(Δ+0.48)}$$	$${36.81\space\color{red}(Δ-2.61)}$$	$${12.94\space\color{green}(Δ-0.04)}$$	$${43.18\space\color{red}(Δ+1.96)}$$	$${13.02\space\color{black}(Δ+0.00)}$$

View metric targets

| Metric | Range | Ideal score | | --- | --- | --- | | [AutomatedReadability](https://en.wikipedia.org/wiki/Automated_readability_index) | 6 (very easy read) to 14 (extremely difficult read) | 8 or less | | [ColemanLiau](https://en.wikipedia.org/wiki/Coleman%E2%80%93Liau_index) | 6 (very easy read) to 17 (extremely difficult read) | 9 or less | | [FleschKincaid](https://en.wikipedia.org/wiki/Flesch%E2%80%93Kincaid_readability_tests) | 6 (very easy read) to 17 (extremely difficult read) | 8 or less | | [FleschReadingEase](https://en.wikipedia.org/wiki/Flesch%E2%80%93Kincaid_readability_tests) | 100 (very easy read) to 0 (extremely difficult read) | 70 or more | | [GunningFog](https://en.wikipedia.org/wiki/Gunning_fog_index) | 6 (very easy read) to 17 (extremely difficult read) | 10 or less | | [LIX](https://en.wikipedia.org/wiki/Lix_(readability_test)) | 20 (very easy read) to 60+ (extremely difficult read) | 35 or less | | [SMOG](https://en.wikipedia.org/wiki/SMOG) | 6 (very easy read) to 17 (extremely difficult read) | 10 or less |