fixed a typo

Author: gareth-d85

html/errata.html

@@ -35,7 +35,7 @@ <h2>Chapter 5</h2>
 <p><strong>Page 91</strong> <em>Composability</em>: Due to an initial
 mistake in the script data set, the results of the computations on
 this page differ from the ones with the current, corrected data. The
-average year for living scrips should be 1165, the average for
+average year for living scripts should be 1165, the average for
 non-living scripts should be 204.</p>
 
 <h2>Chapter 6</h2>