patch 8.1.1901: the +insert_expand feature is not always available

Problem:    The +insert_expand feature is not always available.
Solution:   Graduate the +insert_expand feature.

src/screen.c

@@ -785,10 +785,8 @@ update_screen(int type_arg)
 #if defined(FEAT_SEARCH_EXTRA)
     end_search_hl();
 #endif
-#ifdef FEAT_INS_EXPAND
     /* May need to redraw the popup menu. */
     pum_may_redraw();
-#endif
 
     /* Reset b_mod_set flags.  Going through all windows is probably faster
      * than going through all buffers (there could be many buffers). */
@@ -6877,12 +6875,9 @@ win_redr_status(win_T *wp, int ignore_pum UNUSED)
 	redraw_cmdline = TRUE;
     }
     else if (!redrawing()
-#ifdef FEAT_INS_EXPAND
 	    // don't update status line when popup menu is visible and may be
 	    // drawn over it, unless it will be redrawn later
-	    || (!ignore_pum && pum_visible())
-#endif
-	    )
+	    || (!ignore_pum && pum_visible()))
     {
 	/* Don't redraw right now, do it later. */
 	wp->w_redr_status = TRUE;
@@ -7968,16 +7963,14 @@ screen_char(unsigned off, int row, int col)
     if (row >= screen_Rows || col >= screen_Columns)
 	return;
 
-#ifdef FEAT_INS_EXPAND
     // Skip if under the popup menu.
     // Popup windows with zindex higher than POPUPMENU_ZINDEX go on top.
     if (pum_under_menu(row, col)
-# ifdef FEAT_TEXT_PROP
+#ifdef FEAT_TEXT_PROP
 	    && screen_zindex <= POPUPMENU_ZINDEX
-# endif
+#endif
 	    )
 	return;
-#endif
 #ifdef FEAT_TEXT_PROP
     if (blocked_by_popup(row, col))
 	return;
@@ -9953,9 +9946,7 @@ showmode(void)
     int		do_mode;
     int		attr;
     int		nwr_save;
-#ifdef FEAT_INS_EXPAND
     int		sub_attr;
-#endif
 
     do_mode = ((p_smd && msg_silent == 0)
 	    && ((State & INSERT)
@@ -10010,7 +10001,6 @@ showmode(void)
 		}
 	    }
 #endif
-#ifdef FEAT_INS_EXPAND
 	    /* CTRL-X in Insert mode */
 	    if (edit_submode != NULL && !shortmess(SHM_COMPLETIONMENU))
 	    {
@@ -10041,7 +10031,6 @@ showmode(void)
 		}
 	    }
 	    else
-#endif
 	    {
 		if (State & VREPLACE_FLAG)
 		    msg_puts_attr(_(" VREPLACE"), attr);
@@ -10106,10 +10095,7 @@ showmode(void)
 	    need_clear = TRUE;
 	}
 	if (reg_recording != 0
-#ifdef FEAT_INS_EXPAND
-		&& edit_submode == NULL	    /* otherwise it gets too long */
-#endif
-		)
+		&& edit_submode == NULL)    // otherwise it gets too long
 	{
 	    recording_mode(attr);
 	    need_clear = TRUE;
@@ -10566,14 +10552,12 @@ showruler(int always)
 {
     if (!always && !redrawing())
 	return;
-#ifdef FEAT_INS_EXPAND
     if (pum_visible())
     {
 	/* Don't redraw right now, do it later. */
 	curwin->w_redr_status = TRUE;
 	return;
     }
-#endif
 #if defined(FEAT_STL_OPT)
     if ((*p_stl != NUL || *curwin->w_p_stl != NUL) && curwin->w_status_height)
 	redraw_custom_statusline(curwin);
@@ -10626,9 +10610,8 @@ win_redr_ruler(win_T *wp, int always, int ignore_pum)
     if (wp->w_cursor.lnum > wp->w_buffer->b_ml.ml_line_count)
 	return;
 
-#ifdef FEAT_INS_EXPAND
-    /* Don't draw the ruler while doing insert-completion, it might overwrite
-     * the (long) mode message. */
+    // Don't draw the ruler while doing insert-completion, it might overwrite
+    // the (long) mode message.
     if (wp == lastwin && lastwin->w_status_height == 0)
 	if (edit_submode != NULL)
 	    return;
@@ -10636,7 +10619,6 @@ win_redr_ruler(win_T *wp, int always, int ignore_pum)
     // Except when the popup menu will be redrawn anyway.
     if (!ignore_pum && pum_visible())
 	return;
-#endif
 
 #ifdef FEAT_STL_OPT
     if (*p_ruf)