[gnome-contacts] Add documentation for --search option

[Niels De Graef <nielsdg src gnome org>]

commit d922e0226ea05dba5497ad42cd7729d31cd2b879
Author: Niels De Graef <nielsdegraef gmail com>
Date:   Tue Aug 20 01:28:51 2019 +0200

    Add documentation for --search option
    
    Fixes https://gitlab.gnome.org/GNOME/gnome-contacts/issues/140

 src/contacts-app.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/contacts-app.vala b/src/contacts-app.vala
index 1100b0f..528b222 100644
--- a/src/contacts-app.vala
+++ b/src/contacts-app.vala
@@ -41,7 +41,7 @@ public class Contacts.App : Gtk.Application {
   private const OptionEntry[] options = {
     { "individual",  'i', 0, OptionArg.STRING, null, N_("Show contact with this individual id") },
     { "email",       'e', 0, OptionArg.STRING, null, N_("Show contact with this email address") },
-    { "search",      's', 0, OptionArg.STRING                                                   },
+    { "search",      's', 0, OptionArg.STRING, null, N_("Show contacts with the given filter") },
     { "version",     'v', 0, OptionArg.NONE,   null, N_("Show the current version of Contacts") },
     {}
   };