Edit the bc help a bit
diff --git a/gen/bc_help.txt b/gen/bc_help.txt
index 648ed25..2e3fcb1 100644
--- a/gen/bc_help.txt
+++ b/gen/bc_help.txt
@@ -58,6 +58,8 @@
   3) This bc has many more extensions than the GNU bc does. For details, see the
      man page.
 
+This bc also implements the dot (.) extension of the BSD bc.
+
 Options:
 
   -e  expr  --expression=expr
@@ -94,6 +96,9 @@
           e(expr)  =  raises e to the power of expr
           j(n, x)  =  Bessel function of integer order n of x
 
+      This bc may load more functions with these options. See the manpage for
+      details.
+
   -P  --no-prompt
 
       Disable the prompt in interactive mode.