tweaks: reshuffle a few things to reduce duplication

It is no longer necessary to assign up() and down() separately for
the help viewer because by now the movement keys have been sorted
in order of ascending stride also in the main menu.

The two string definitions are relocated just to reduce the number
of #ifdefs.

src/global.c

@@ -493,11 +493,8 @@ void shortcut_init(void)
     const char *whereis_next_tag = N_("WhereIs Next");
 
 #ifdef ENABLE_HELP
-#ifndef DISABLE_JUSTIFY
     /* TRANSLATORS: The next long series of strings are shortcut descriptions;
      * they are best kept shorter than 56 characters, but may be longer. */
-    const char *nano_justify_msg = N_("Justify the current paragraph");
-#endif
     const char *nano_cancel_msg = N_("Cancel the current function");
     const char *nano_help_msg = N_("Display this help text");
     const char *nano_exit_msg =
@@ -589,6 +586,7 @@ void shortcut_init(void)
 	N_("Cut from the cursor position to the end of the file");
 #endif
 #ifndef DISABLE_JUSTIFY
+    const char *nano_justify_msg = N_("Justify the current paragraph");
     const char *nano_fulljustify_msg = N_("Justify the entire file");
 #endif
 #ifndef NANO_TINY
@@ -623,9 +621,6 @@ void shortcut_init(void)
     const char *nano_next_history_msg =
 	N_("Recall the next search/replace string");
 #endif
-#ifdef ENABLE_BROWSER
-    const char *nano_tofiles_msg = N_("Go to file browser");
-#endif
 #ifndef NANO_TINY
     const char *nano_dos_msg = N_("Toggle the use of DOS format");
     const char *nano_mac_msg = N_("Toggle the use of Mac format");
@@ -639,6 +634,7 @@ void shortcut_init(void)
 #endif
     const char *nano_discard_buffer_msg = N_("Close buffer without saving it");
 #ifdef ENABLE_BROWSER
+    const char *nano_tofiles_msg = N_("Go to file browser");
     const char *nano_exitbrowser_msg = N_("Exit from the file browser");
     const char *nano_firstfile_msg = N_("Go to the first file in the list");
     const char *nano_lastfile_msg = N_("Go to the last file in the list");
@@ -671,7 +667,7 @@ void shortcut_init(void)
     add_to_funcs(do_cancel, ((MMOST & ~MMAIN & ~MBROWSER) | MYESNO),
 	N_("Cancel"), IFSCHELP(nano_cancel_msg), BLANKAFTER, VIEW);
 
-    add_to_funcs(do_exit, MMAIN,
+    add_to_funcs(do_exit, MMAIN|MHELP,
 	exit_tag, IFSCHELP(nano_exit_msg), TOGETHER, VIEW);
     /* Remember the entry for Exit, to be able to replace it with Close. */
     exitfunc = tailfunc;
@@ -724,15 +720,10 @@ void shortcut_init(void)
 #ifdef ENABLE_HELP
     /* The description ("x") and blank_after (0) are irrelevant,
      * because the help viewer does not have a help text. */
-    add_to_funcs(do_exit, MHELP, exit_tag, "x", 0, VIEW);
-
     add_to_funcs(total_refresh, MHELP, refresh_tag, "x", 0, VIEW);
 
     add_to_funcs(do_search, MHELP, whereis_tag, "x", 0, VIEW);
     add_to_funcs(do_research, MHELP, whereis_next_tag, "x", 0, VIEW);
-
-    add_to_funcs(do_up_void, MHELP, prev_line_tag, "x", 0, VIEW);
-    add_to_funcs(do_down_void, MHELP, next_line_tag, "x", 0, VIEW);
 #endif
 
     add_to_funcs(do_cut_text_void, MMAIN,
@@ -841,9 +832,9 @@ void shortcut_init(void)
     add_to_funcs(do_end_void, MMAIN,
 	N_("End"), IFSCHELP(nano_end_msg), BLANKAFTER, VIEW);
 
-    add_to_funcs(do_up_void, MMAIN|MBROWSER,
+    add_to_funcs(do_up_void, MMAIN|MHELP|MBROWSER,
 	prev_line_tag, IFSCHELP(nano_prevline_msg), TOGETHER, VIEW);
-    add_to_funcs(do_down_void, MMAIN|MBROWSER,
+    add_to_funcs(do_down_void, MMAIN|MHELP|MBROWSER,
 	next_line_tag, IFSCHELP(nano_nextline_msg), TOGETHER, VIEW);
 #ifndef NANO_TINY
     add_to_funcs(do_scroll_up, MMAIN,