[umount] Fix schema -- prefer *preservefiles* for keeping the log

src/modules/umount/umount.conf

@@ -2,35 +2,15 @@
 #
 # This module represents the last part of the installation, the unmounting
 # of partitions used for the install.  It is also the last place where it
-# is possible to copy files to the target system, thus the best place to
-# copy an installation log.
+# is possible to copy files to the target system.
+#
+# The "copy log files" functionality is deprecated; use the *preservefiles*
+# module instead, which is more flexible.
 #
 # This module has two configuration keys:
 #   srcLog  location in the live system where the log is
 #   destLog location in the target system to copy the log
 #
-# You can either use the default source path (which is
-# `/root/.cache/calamares/session.log` ) to copy the regular log,
-# or if you want to use the full output of `sudo calamares -d` you will need
-# to redirect standard output, for instance in a launcher script or
-# in the desktop file.
-#
-# Example launcher script:
-#
-# ```
-# #!/bin/sh
-# sudo /usr/bin/calamares -d > installation.log
-# ```
-#
-# Example desktop line:
-#
-# ```
-# Exec=sudo /usr/bin/calamares -d > installation.log
-# ```
-#
-# If no source and destination are set, no copy is attempted. If the
-# copy fails for some reason, a warning is printed but the installation
-# does not fail.
 
 ---
 # example when using the normal Calamares log:

src/modules/umount/umount.schema.yaml

@@ -4,5 +4,5 @@ $id: https://calamares.io/schemas/umount
 additionalProperties: false
 type: object
 properties:
-    "srcLog": { type: str }
-    "destLog": { type: str }
+    srcLog: { type: string }
+    destLog: { type: string }