chore(@gatsbyjs/parcel-namer-relative-to-cwd): Improve README (#38049)

Author: LekoArts

packages/gatsby-parcel-namer-relative-to-cwd/README.md

@@ -1,6 +1,27 @@
 # `@gatsbyjs/parcel-namer-relative-to-cwd`
 
-Parcel by default is trying to find common/shared directory between entries and output paths are impacted by it. See https://github.com/parcel-bundler/parcel/issues/5476#issuecomment-769058504.
+This [namer plugin](https://parceljs.org/plugin-system/namer/) is used by [Gatsby](https://www.gatsbyjs.com/) internally. You can reuse it inside your app if you want.
+
+If you're just using Gatsby, you don't need to care about this package/plugin.
+
+## Usage
+
+```shell
+npm install --save-dev @gatsbyjs/parcel-namer-relative-to-cwd
+```
+
+And inside your `.parcelrc`:
+
+```
+{
+  "extends": "@parcel/config-default",
+  "namers": ["@gatsbyjs/parcel-namer-relative-to-cwd", "..."]
+}
+```
+
+## Why & How
+
+By default, Parcel is trying to find common/shared directories between entries and output paths that are impacted by it. See [this issue comment](https://github.com/parcel-bundler/parcel/issues/5476#issuecomment-769058504) for more information.
 
 With these inputs files:
 
@@ -15,9 +36,9 @@ You get:
 - `parcel build sub/b.html` => `dist/b.html`
 - `parcel build a.html sub/b.html` => `dist/a.html`, `dist/sub/b.html`
 
-We can see that `sub/b.html` entry might result in either `dist/b.html` or `dist/sub/b.html` (depending wether `a.html` is entry or not). This makes builds not deterministic, which is very problematic where entries are "optional".
+You can see that `sub/b.html` entry might result in either `dist/b.html` or `dist/sub/b.html` (depending wether `a.html` is entry or not). This makes builds not deterministic, which is very problematic where entries are "optional".
 
-This namer plugin stabilize output, so inside `distDir` the hierarchy is the same as entry file in relation to current working directory (CWD):
+This namer plugin stabilizes the output, so inside `distDir` the hierarchy is the same as entry file in relation to current working directory (CWD):
 
 - `parcel build a.html` => `dist/a.html`
 - `parcel build sub/b.html` => `dist/sub/b.html`

packages/gatsby-parcel-namer-relative-to-cwd/package.json

@@ -3,7 +3,7 @@
   "main": "lib/index.js",
   "version": "2.10.0-next.1",
   "homepage": "https://github.com/gatsbyjs/gatsby/tree/master/packages/gatsby-parcel-namer-relative-to-cwd#readme",
-  "description": "Parcel namer that preserve directory structure to stabilize output and keep the hierarchy.",
+  "description": "Parcel namer that preserves directory structures to stabilize output and keep the hierarchy.",
   "author": "Michal Piechowiak <[email protected]>",
   "repository": {
     "type": "git",