Merge pull request rails#42618 from AkhilGKrishnan/guides-punctuation-issue-fix

Fix punctuation of layout and rendering doc

Author: zzak

guides/source/layouts_and_rendering.md

@@ -889,9 +889,9 @@ To include `http://example.com/main.js`:
 
 The [`stylesheet_link_tag`][] helper returns an HTML `<link>` tag for each source provided.
 
-If you are using Rails with the "Asset Pipeline" enabled, this helper will generate a link to `/assets/stylesheets/`. This link is then processed by the Sprockets gem. A stylesheet file can be stored in one of three locations: `app/assets`, `lib/assets` or `vendor/assets`.
+If you are using Rails with the "Asset Pipeline" enabled, this helper will generate a link to `/assets/stylesheets/`. This link is then processed by the Sprockets gem. A stylesheet file can be stored in one of three locations: `app/assets`, `lib/assets`, or `vendor/assets`.
 
-You can specify a full path relative to the document root, or a URL. For example, to link to a stylesheet file that is inside a directory called `stylesheets` inside of one of `app/assets`, `lib/assets` or `vendor/assets`, you would do this:
+You can specify a full path relative to the document root, or a URL. For example, to link to a stylesheet file that is inside a directory called `stylesheets` inside of one of `app/assets`, `lib/assets`, or `vendor/assets`, you would do this:
 
 ```erb
 <%= stylesheet_link_tag "main" %>