doc: Move and update documentation for --no-scan

doc/040_backup.rst

@@ -204,16 +204,6 @@ Combined with ``--verbose``, you can see a list of changes:
     modified  /archive.tar.gz, saved in 0.140s (25.542 MiB added)
     Would be added to the repository: 25.551 MiB
 
-Disabling Backup Progress Estimation
-************************************
-
-When you start a backup, restic will concurrently count the number of
-files and their total size, which is used to estimate how long it will
-take.  This will cause some extra I/O, which can slow down backup of
-network file systems or fuse mounts.
-
--  ``--no-scan``  Do not run scanner to estimate size of backup
-
 .. _backup-excluding-files:
 Excluding Files
 ***************

doc/047_tuning_backup_parameters.rst

@@ -19,6 +19,15 @@ values. As the restic commands evolve over time, the optimal value for each para
 can also change across restic versions.
 
 
+Disabling Backup Progress Estimation
+************************************
+
+When you start a backup, restic will concurrently count the number of files and
+their total size, which is used to estimate how long it will take. This will
+cause some extra I/O, which can slow down backups of network file systems or
+FUSE mounts. To avoid this overhead at the cost of not seeing a progress
+estimate, use the ``--no-scan`` option which disables this file scanning.
+
 Backend Connections
 ===================