include higher ground rules

combat.tex

@@ -704,6 +704,12 @@ cannot use their Dexterity Bonus in Combat (penalties still apply), and take a -
 Attacks against a \textit{Prone} target gain a +2 bonus.
 However, they can get up as by spending 1 \gls{ap}.
 
+\subsubsection[+1 to attack]{Higher Ground}
+\index{Prone}
+\label{prone}
+
+Gaining the higher ground grants +1 to the Attack Bonus, as you target the enemy's head easier and gravity aids your downward swings.
+
 \subsection{Manoeuvres}
 
 These additional actions cover different ways to engage with enemies.