[seahorse] help: Sync format of two strings to be consistent with other pages

[Andre Klapper <aklapper src gnome org>]

commit 2c156b1d8597d82a0d732afab5cd39f6d4934521
Author: Andre Klapper <a9016009 gmx de>
Date:   Fri May 22 12:49:26 2020 +0200

    help: Sync format of two strings to be consistent with other pages
    
    Fixes #270

 help/C/pgp-export.page | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/help/C/pgp-export.page b/help/C/pgp-export.page
index 5f4ca9f7..cc526279 100644
--- a/help/C/pgp-export.page
+++ b/help/C/pgp-export.page
@@ -26,7 +26,7 @@
   backup of your keys or to share your public key with someone.</p>
 
   <section id="public">
-    <title>To export your public PGP key</title>
+    <title>To export your public PGP key:</title>
 
     <steps>
       <item>
@@ -55,7 +55,7 @@
 
 <!-- TODO: Wrong in 3.32, see https://gitlab.gnome.org/GNOME/seahorse/issues/220 -->
   <section id="private">
-    <title>To export your private PGP key</title>
+    <title>To export your private PGP key:</title>
 
     <steps>
       <item>