more miscellaneous minor maintenance

Notable changes:

src/cmd/ksh93/edit/emacs.c:
- Remove !ESH_NFIRST, !ESH_KAPPEND and !ESH_BETTER dead code, and
  those symbols. These features were added between 1986 and 1988.
  No one compiles emacs.c without them. For distinguishing these
  features, we have the git history.

src/cmd/ksh93/sh.1:
- Finally document the emacs.c features mentioned above.

src/cmd/builtin/Mamfile:
- Fix a library dependency bug. pty(1) was not getting relinked
  when libast or libcmd changes. The 'bind' command must be within
  the 'make pty' block for pty to depend on them.

COPYRIGHT

@@ -28,6 +28,7 @@ ksh 93u+m general copyright notice
 #                   Chase <[email protected]>                   #
 #           rymrg <[email protected]>            #
 #       hyousatsu <[email protected]>       #
+#             dnewhall <[email protected]>             #
 #                      Trey Valenta <[email protected]>                       #
 #  Sterling Jensen <[email protected]>   #
 #                   Marc Wilson <[email protected]>                   #

src/cmd/builtin/Mamfile

@@ -14,14 +14,14 @@ setv IFFEFLAGS
 setv LDFLAGS
 
 make install virtual
-	bind -lcmd
-	bind -lutil dontcare
 
 	note *
 	note * Build pty
 	note *
 
 	make pty
+		bind -lcmd
+		bind -lutil dontcare
 		make pty.o
 			make pty.c
 				make FEATURE/pty