A11y (#416)

* Update course format for accessibility

* Update README.md

* manual fixes

Author: heiskr

.github/steps/1-create-a-branch.md

@@ -15,7 +15,7 @@ _Welcome to "Introduction to GitHub"! :wave:_
 
 **What is a repository?**: A _[repository](https://docs.github.com/get-started/quickstart/github-glossary#repository)_ is a project containing files and folders. A repository tracks versions of files and folders. For more information, see "[About repositories](https://docs.github.com/en/repositories/creating-and-managing-repositories/about-repositories)" from GitHub Docs.
 
-**What is a branch?**: A _[branch](https://docs.github.com/en/get-started/quickstart/github-glossary#branch)_ is a parallel version of your repository. By default, your repository has one branch named `main` and it is considered to be the definitive branch.  Creating additional branches allows you to copy the `main` branch of your repository and safely make any changes without disrupting the main project. Many people use branches to work on specific features without affecting any other parts of the project.
+**What is a branch?**: A _[branch](https://docs.github.com/en/get-started/quickstart/github-glossary#branch)_ is a parallel version of your repository. By default, your repository has one branch named `main` and it is considered to be the definitive branch. Creating additional branches allows you to copy the `main` branch of your repository and safely make any changes without disrupting the main project. Many people use branches to work on specific features without affecting any other parts of the project.
 
 Branches allow you to separate your work from the `main` branch. In other words, everyone's work is safe while you contribute. For more information, see "[About branches](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/about-branches)".
 

.github/steps/2-commit-a-file.md

@@ -34,7 +34,7 @@ The following steps will guide you through the process of committing a change on
 
    <img alt="profile.md file screenshot" src="/images/my-profile-file.png"/>
 
-5. Click **Commit changes...** in the upper right corner above the contents box. For commits, you can enter a short commit message that describes what changes you made. This message helps others know what's included in your commit. GitHub offers a simple default message, but let's change it slightly for practice. First, enter `Add PROFILE.md` in the first text-entry field titled "Commit message". 
+5. Click **Commit changes...** in the upper right corner above the contents box. For commits, you can enter a short commit message that describes what changes you made. This message helps others know what's included in your commit. GitHub offers a simple default message, but let's change it slightly for practice. First, enter `Add PROFILE.md` in the first text-entry field titled "Commit message".
 
    <img alt="screenshot of adding a new file with a commit message" src="/images/commit-full-screen.png" />