Update documentation to require coreutils when runniung the http server on macOS.

Author: paoloczi

docs/InspectingResults.html

@@ -68,7 +68,7 @@ <h1>Exploring assembly results</h1>
 
 
 
-<h2>Starting the Shasta http server on Linux</h2>
+<h2 id=Linux>Starting the Shasta http server on Linux</h2>
 <p>
 The Shasta http server uses 
 <a href="https://www.graphviz.org/">Graphviz</a> software to display graphs.
@@ -121,11 +121,12 @@ <h2>Starting the Shasta http server on Linux</h2>
 
 
 
-<h2>Starting the Shasta http server on macOS</h2>
+<h2 id=macOS>Starting the Shasta http server on macOS</h2>
 <p>
 The Shasta http server uses 
 <a href="https://www.graphviz.org/">Graphviz</a> software to display graphs.
-To install it, use this command: <pre>brew install graphviz</pre>
+It also needs command <code>gtimeout</code> which is part of the coreutils package.
+To install them, use this command: <pre>brew install graphviz coreutils</pre>
 <p>
 To start the Shasta http server on macOS, follow these steps:
 <ol>
@@ -211,7 +212,7 @@ <h2 id=AccessControl>Access control</h2>
 
 <h2>Screenshots</h2>
 <p>
-Below are some sampel screenshots obtained using 
+Below are some sample screenshots obtained using 
 <code>--command explore</code>.
 
 <hr><img style='width:100%' src="InspectingResults-Images/1.png">