[rhythmbox] help: Fix more typos

[Andre Klapper <aklapper src gnome org>]

commit 564ab19a796d82eb93880351f751aaf54e286f5c
Author: Andre Klapper <a9016009 gmx de>
Date:   Thu Jan 2 23:26:01 2020 +0100

    help: Fix more typos

 help/C/index.docbook | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/help/C/index.docbook b/help/C/index.docbook
index 80ced0e99..e97933db9 100644
--- a/help/C/index.docbook
+++ b/help/C/index.docbook
@@ -524,10 +524,10 @@
                        your music files, not the files themself).
                </para>
        <para>
-                       The Library can not only contains music files which are physically 
+                       The Library can not only contain music files which are physically 
                        on your computer (in your HOME Directory for instance), but it can
-                       also contains music files available over remote network services. 
-                       Some examples of supported network services are :
+                       also contain music files available over remote network services. 
+                       Some examples of supported network services are:
                        <itemizedlist>
                                <listitem>
                                        <para>Public FTP</para>