specify travel fatigue rules

rules/fatigue.tex

 \begin{itemize}
   \item
   Every strenuous activity inflicts one \gls{fatigue}.
+  \begin{itemize}
+    \item
+    Marching through a mile of forest inflicts \pgls{fatigue}.
+    \item
+    Marching along two miles of road inflicts \pgls{fatigue}.
+    \item
+    Every fight inflicts \pgls{fatigue}.
+  \end{itemize}
   \item
   Every \gls{fatigue} a character has above their current \glspl{hp} inflicts a -1 penalty to all actions.
   \item