Fixed typo.

Author: janpgit

docs/index.html

@@ -136,8 +136,8 @@ <h2><a name="final_assignment">Final Lab Assignment</a></h2>
 tests at least on one of the Linux machines u-pl* in the MFF UK lab at
 Mal&aacute; Strana.  Which one should not matter as their configuration is
 expected to be identical.  See <a href="#unix_access">Unix machine access</a>
-above for more information.  So, that means it is up to you what Linux distro or
-Unix-like system you choose to develop your shell on but you must be able to
+above for more information.  So, that means it is up to you what a Linux distro
+or Unix-like system you choose to develop your shell on but you must be able to
 build it and verify the tests on a u-pl* machine as well.
 
 <p>