[evince] shell: Fix regression on F3 shortcut

[Germán Poo-Caamaño <gpoo src gnome org>]

commit 38419c96c06086eb622fae696ca375ba4dcf93df
Author: Germán Poo-Caamaño <gpoo gnome org>
Date:   Thu Jun 28 18:26:05 2018 -0400

    shell: Fix regression on F3 shortcut
    
    F3 used to be available for find_next entry.  With the migration from
    old toolbars to the headerbar, these shortcuts was lost.
    Additionally, I added <Shift>F3 for finding the previous one.
    
    commit 8bb5fce0 removed them, likely it was an oversight.
    
    Closes #595

 shell/ev-application.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/shell/ev-application.c b/shell/ev-application.c
index 9bb7a066..9586d1a3 100644
--- a/shell/ev-application.c
+++ b/shell/ev-application.c
@@ -1053,8 +1053,8 @@ ev_application_startup (GApplication *gapplication)
           "win.close",                  "<Ctrl>W", NULL,
           "win.escape",                 "Escape", NULL,
           "win.find",                   "<Ctrl>F", "slash", NULL,
-          "win.find-next",              "<Ctrl>G", NULL,
-          "win.find-previous",          "<Ctrl><Shift>G", NULL,
+          "win.find-next",              "<Ctrl>G", "F3", NULL,
+          "win.find-previous",          "<Ctrl><Shift>G", "<Shift>F3", NULL,
           "win.select-page",            "<Ctrl>L", NULL,
           "win.go-backwards",           "<Shift>Page_Up", NULL,
           "win.go-forward",             "<Shift>Page_Down", NULL,