Fix syntax with alt text

episodes/07-github.md

@@ -68,7 +68,7 @@ which looked like this:
 
 Now that we have two repositories, we need a diagram like this:
 
-![](fig/git-freshly-made-github-repo.svg) {alt='A diagram illustrating how the GitHub "planets" repository is also a git repository like our local repository, but that it is currently empty'}
+![](fig/git-freshly-made-github-repo.svg){alt='A diagram illustrating how the GitHub "planets" repository is also a git repository like our local repository, but that it is currently empty'}
 
 Note that our local repository still contains our earlier work on `mars.txt`, but the
 remote repository on GitHub appears empty as it doesn't contain any files yet.
@@ -80,7 +80,7 @@ GitHub repository a [remote](../learners/reference.md#remote) for the local repo
 The home page of the repository on GitHub includes the URL string we need to
 identify it:
 
-![](fig/github-find-repo-string.png){alt='Clicking the "Copy to Clipboard" button on GitHub to obtain the repository's URL'}
+![](fig/github-find-repo-string.png){alt='Clicking the "Copy to Clipboard" button on GitHub to obtain the repository\'s URL'}
 
 Click on the 'SSH' link to change the [protocol](../learners/reference.md#protocol) from HTTPS to SSH.