Update g.gisenv.html (#219)

Older users know about sh too. So mention it.

general/g.gisenv/g.gisenv.html

@@ -138,8 +138,8 @@ following command will cast each variable into the UNIX environment:
 eval `g.gisenv`
 </pre></div>
 
-This works only for <em>Bash</em>. The format of the output is not
-compatible with other UNIX shells.
+This works only for <em>Bash</em>, <em>sh</em>, <em>ksh</em>, etc. The format of the output is not
+compatible with some other UNIX shells.
 
 <p>
 By default the GRASS variables are stored in <em>gisrc</em> file