Remove SH_NOLOG vestiges

The '-o nolog' option (which prevented function definitions from being
recorded in the history file) was removed a long time ago, leaving
only a stub for backwards compatibility to stop 'set' from erroring
out if the option is set. But some other vestiges remained.

src/cmd/ksh93/sh/path.c,
src/cmd/ksh93/sh/subshell.c,
src/cmd/ksh93/sh/xec.c:
- Remove a few pointless 'sh_onstate(SH_NOLOG)' statements. As of
  93u+ or earlier, this is never checked for anywhere.

src/cmd/ksh93/sh.1:
- They forgot to remove the 'nolog' option documentation here.
  Specify that it's obsolete and has no effect.

src/cmd/ksh93/data/builtins.c: sh_set[]:
- Be more concise.

src/cmd/ksh93/data/builtins.c

@@ -230,8 +230,7 @@ const char sh_set[] =
 		"[+noclobber?Equivalent to \b-C\b.]"
 		"[+noexec?Equivalent to \b-n\b.]"
 		"[+noglob?Equivalent to \b-f\b.]"
-		"[+nolog?This has no effect.  It is provided for backward "
-			"compatibility.]"
+		"[+nolog?Obsolete; has no effect.]"
 		"[+notify?Equivalent to \b-b\b.]"
 		"[+nounset?Equivalent to \b-u\b.]"
 		"[+pipefail?A pipeline will not complete until all components "

src/cmd/ksh93/sh.1

@@ -7062,7 +7062,7 @@ Same as
 .BR \-f .
 .TP 8
 .B nolog
-Do not save function definitions in the history file.
+Obsolete; has no effect.
 .TP 8
 .B notify
 Same as

src/cmd/ksh93/sh/path.c

@@ -610,7 +610,6 @@ static void funload(Shell_t *shp,int fno, const char *name)
 		free((void*)pname);
 		return;
 	}
-	sh_onstate(SH_NOLOG);
 	sh_onstate(SH_NOALIAS);
 	shp->readscript = (char*)name;
 	shp->st.filename = pname;

src/cmd/ksh93/sh/subshell.c

@@ -206,7 +206,6 @@ void sh_subfork(void)
 		/* this is the child part of the fork */
 		/* setting subpid to 1 causes subshell to exit when reached */
 		sh_onstate(SH_FORKED);
-		sh_onstate(SH_NOLOG);
 		sh_offoption(SH_MONITOR);
 		sh_offstate(SH_MONITOR);
 		subshell_data = 0;

src/cmd/ksh93/sh/xec.c

@@ -2919,7 +2919,6 @@ pid_t _sh_fork(Shell_t *shp,register pid_t parent,int flags,int *jobid)
 	shp->login_sh = 0;
 	sh_offoption(SH_LOGIN_SHELL);
 	sh_onstate(SH_FORKED);
-	sh_onstate(SH_NOLOG);
 	if (shp->fn_reset)
 		shp->fn_depth = shp->fn_reset = 0;
 #if SHOPT_ACCT