patch 9.0.0883: a silent mapping may cause dots on the command line

Problem:    A silent mapping may cause dots on the command line.
Solution:   Don't show dots for completion if they are not going to be removed
            again. (closes #11501)

runtime/doc/map.txt

@@ -234,6 +234,9 @@ The search string will not be echoed when using this mapping.  Messages from
 the executed command are still given though.  To shut them up too, add a
 ":silent" in the executed command: >
 	:map <silent> ,h :exe ":silent normal /Header\r"<CR>
+Note that the effect of a command might also be silenced, e.g., when the
+mapping selects another entry for command line completion it won't be
+displayed.
 Prompts will still be given, e.g., for inputdialog().
 Using "<silent>" for an abbreviation is possible, but will cause redrawing of
 the command line to fail.

src/cmdexpand.c

@@ -226,8 +226,13 @@ nextwild(
 	return FAIL;
     }
 
-    msg_puts("...");	    // show that we are busy
+    // If cmd_silent is set then don't show the dots, because redrawcmd() below
-    out_flush();
+    // won't remove them.
+    if (!cmd_silent)
+    {
+	msg_puts("...");	    // show that we are busy
+	out_flush();
+    }
 
     i = (int)(xp->xp_pattern - ccline->cmdbuff);
     xp->xp_pattern_len = ccline->cmdpos - i;

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    883,
 /**/
     882,
 /**/