Update links for new filename

wiki/src/doc/first_steps.index.mdwn

@@ -11,7 +11,7 @@
     - [[!traillink Warnings_about_the_Persistent_Storage|first_steps/persistence/warnings]]
     - [[!traillink Creating_and_configuring_the_Persistent_Storage|first_steps/persistence/configure]]
     - [[!traillink Unlocking_and_using_the_Persistent_Storage|first_steps/persistence/use]]
-    - [[!traillink Making_a_backup_of_your_Persistent_Storage|first_steps/persistence/copy]]
+    - [[!traillink Making_a_backup_of_your_Persistent_Storage|first_steps/persistence/backup]]
     - [[!traillink Rescuing_your_Persistent_Storage|first_steps/persistence/rescue]]
     - [[!traillink Deleting_the_Persistent_Storage|first_steps/persistence/delete]]
   - [[!traillink Installing_additional_software|first_steps/additional_software]]

wiki/src/doc/first_steps/persistence.mdwn

@@ -26,6 +26,6 @@ How to use the Persistent Storage
   - [[Warnings about the Persistent Storage|first_steps/persistence/warnings]]
   - [[Creating and configuring the Persistent Storage|first_steps/persistence/configure]]
   - [[Unlocking and using the Persistent Storage|first_steps/persistence/use]]
-  - [[Making a backup of your Persistent Storage|first_steps/persistence/copy]]
+  - [[Making a backup of your Persistent Storage|first_steps/persistence/backup]]
   - [[Rescuing your Persistent Storage|first_steps/persistence/rescue]]
   - [[Deleting the Persistent Storage|first_steps/persistence/delete]]

wiki/src/doc/first_steps/persistence/configure.mdwn

@@ -60,7 +60,7 @@ for more details.<p>
 
 <p>If you turn off a feature, it will be
 unavailable after restarting Tails but the
-[[corresponding files|doc/first_steps/persistence/copy#feature_files]]
+[[corresponding files|doc/first_steps/persistence/backup#feature_files]]
 are still saved in the Persistent Storage.</p>
 
 <p>To delete the files corresponding to a feature:</p>

wiki/src/news/report_2019_09.mdwn

@@ -43,7 +43,7 @@ Documentation and website
 =========================
 
 - We rewrote completely the instructions to [[backup the persistent
-  volume|doc/first_steps/persistence/copy]].
+  volume|doc/first_steps/persistence/backup]].
 
 - We documented how to do right-click on Mac. ([[!tails_ticket 15718]])
 

wiki/src/news/report_2020_01.mdwn

@@ -97,7 +97,7 @@ Documentation and website
   to display progress (`status=progress`) and sync on-the-fly (`oflag=direct`).
 
 - We fixed the display of the output of `rsync` when doing a [[backup of the
-  persistent volume|doc/first_steps/persistence/copy]].
+  persistent volume|doc/first_steps/persistence/backup]].
 
 Hot topics on our help desk
 ===========================

wiki/src/news/version_4.0.mdwn

@@ -147,7 +147,7 @@ especially for non-English users:
   including USB sticks and SSDs.
 
 - [[How to backup your persistent
-  volume|doc/first_steps/persistence/copy]].
+  volume|doc/first_steps/persistence/backup]].
 
 ## Other changes