copy-edits for README (#30)

Author: rachelsaunders

README.md

@@ -2,12 +2,12 @@
 
 ## Usage
 
-### Deploy a to a new preview channel for every PR
+### Deploy to a new preview channel for every PR
 
 Add a workflow (`.github/workflows/deploy-preview.yml`):
 
 ```yaml
-name: Deploy Preview
+name: Deploy to Preview Channel
 
 on:
   pull_request:
@@ -32,12 +32,12 @@ jobs:
           FIREBASE_CLI_PREVIEWS: hostingchannels
 ```
 
-### Deploy to your live site on merge
+### Deploy to your live channel on merge
 
 Add a workflow (`.github/workflows/deploy-prod.yml`):
 
 ```yaml
-name: Deploy Production Site
+name: Deploy to Live Channel
 
 on:
   push:
@@ -71,41 +71,45 @@ This is a service account JSON key.
 
 It's important to store this token as an
 [encrypted secret](https://help.github.com/en/actions/configuring-and-managing-workflows/creating-and-storing-encrypted-secrets)
-to prevent unintended access your Firebase project. Set it in the "Secrets" area
+to prevent unintended access to your Firebase project. Set it in the "Secrets" area
 of your repository settings and add it as `FIREBASE_SERVICE_ACCOUNT`:
-`https://github.com/USERNAME/REPOSITORY/settings/secrets`
+`https://github.com/USERNAME/REPOSITORY/settings/secrets`.
 
 ### `repoToken` _{string}_
 
 Adding `repoToken: "${{secrets.GITHUB_TOKEN}}"` lets the action comment on PRs
-with the link to the deploy preview. You don't need to set this secret
-yourself - github will set it automatically.
+with the preview URL for the associated preview channel. You don't need to set
+this secret yourself - GitHub sets it automatically.
 
 If you omit this option, you'll need to find the preview URL in the action's
 build log.
 
 ### `expires` _{string}_
 
-The length of time the channel should live. If left blank, uses the Firebase Hosting default expiry (7 days).
+The length of time the preview channel should remain active.
+If left blank, the action uses the default expiry of 7 days.
 
 ### `projectId` _{string}_
 
-The project to deploy to. If you leave this blank, be sure to check in a
-`.firebaserc` file so the CLI knows what project to deploy to.
+The Firebase project that contains the Hosting site to which you
+want to deploy. If left blank, you need to check in a `.firebaserc`
+file so that the Firebase CLI knows which Firebase project to use.
 
 ### `channelId` _{string}_
 
-The channel to deploy to. If you don't set it, a new channel will be created
-per-PR or per-branch. If you set it to **`live`**, the action will deploy to your production Hosting site.
+The channel to deploy to. If you don't set it, the action creates
+a new preview channel per-PR or per-branch. If you set it to **`live`**,
+the action deploys to the live channel of your default Hosting site.
 
-You usually want to leave this blank so that each PR gets its own channel,
-unless you know you want to deploy a certain branch to a long-lived channel (for
-example, you may want to deploy every commit from your `next` branch to a
-`preprod` channel)
+You usually want to leave this blank so that each PR gets its own preview channel.
+An exception might be that you always want to deploy a certain branch to a
+long-lived preview channel (for example, you may want to deploy every commit
+from your `next` branch to a `preprod` preview channel).
 
 ### `entryPoint` _{string}_
 
-The location of your [`firebase.json`](https://firebase.google.com/docs/cli#the_firebasejson_file) file relative to the root of your repository. Defaults to `.` (the root of your repo).
+The location of your [`firebase.json`](https://firebase.google.com/docs/cli#the_firebasejson_file)
+file relative to the root of your repository. Defaults to `.` (the root of your repo).
 
 ---