Update writing checklist to mention .gitignore file

BlankProjectTemplate/docs/Writing-Checklist.tex

@@ -66,9 +66,11 @@
   \item All sentences begin with a capital letter.
   \item Document is spell checked!
   \item Grammar has been checked.
-    \item Symbols used outside of a formula should be formatted the same way as
-      they are in the equation.  For instance, when listing the variables in an
-      equation, you should still use math mode for the symbols.
+  \item Symbols used outside of a formula should be formatted the same way as
+    they are in the equation.  For instance, when listing the variables in an
+    equation, you should still use math mode for the symbols.
+  \item Include a .gitignore file in your repo so that generated files are
+    ignored by git
   \end{todolist}
 
 \item Writing style