Added FA and SRG stuff to HelpFile. Fixed typos in history file.

doc/gf-history.html

@@ -24,7 +24,7 @@ The new options are:
 <dt><tt>pg -printer=slf_graphviz</tt></dt>
 <dd>The same FA as in SLF, but in Graphviz format.</dd>
 <dt><tt>pg -printer=fa_graphviz</tt></dt>
-<dd>An FA with labelled edges, instead of labelled nodes which SLF has.</dd>
+<dd>A finite automaton with labelled edges, instead of labelled nodes which SLF has.</dd>
 <dt><tt>pg -printer=regular</tt></dt>
 <dd>A regular grammar in a simple BNF.</dd>
 </dl>