chore(docs): reword CSS in JS docs for clarity

docs/docs/glamor.md

@@ -19,7 +19,7 @@ First, open a new terminal window and run the following to create a new site:
 gatsby new glamor-tutorial https://github.com/gatsbyjs/gatsby-starter-hello-world
 ```
 
-Second, install the Gatsby plugin for Glamor.
+Second, we’ll install the necessary dependencies for Glamor and Gatsby.
 
 ```shell
 npm install --save gatsby-plugin-glamor glamor

docs/docs/styled-components.md

@@ -20,7 +20,7 @@ First, open a new terminal window and run the following to create a new site:
 gatsby new styled-components-tutorial https://github.com/gatsbyjs/gatsby-starter-hello-world
 ```
 
-Next, we'll install the necessary dependencies for `styled-components`, including the Gatsby plugin.
+Second, we'll install the necessary dependencies for `styled-components`, including the Gatsby plugin.
 
 ```shell
 npm install --save gatsby-plugin-styled-components styled-components babel-plugin-styled-components