[unpackfs] Shuffle the documentation

- move all the examples to an EXAMPLES section
 - leave one single-file example enabled in the configuration

src/modules/unpackfs/unpackfs.conf

@@ -19,33 +19,49 @@
 #       - *file* (copies a file or directory)
 #       - (may be others if mount supports it)
 #   destination: path relative to rootMountPoint (so in the target
-#       system) where this filesystem is unpacked.
-unpack:
-
+#       system) where this filesystem is unpacked. It may be an
+#       empty string, which effectively is / (the root) of the target
+#       system.
+#
+# EXAMPLES
+#
 # Usually you list a filesystem image to unpack; you can use
 # squashfs or an ext4 image.
 #
 #   -   source: "/path/to/filesystem.sqfs"
 #       sourcefs: "squashfs"
 #       destination: ""
-
-# You can list more than one filesystem.
+#
+# Multiple entries are unpacked in-order
 #
 #   -   source: "/path/to/another/filesystem.img"
 #       sourcefs: "ext4"
 #       destination: ""
+#   -   source: "/path/to/another/filesystem2.img"
+#       sourcefs: "ext4"
+#       destination: "/usr/lib/extra"
 #
-
 # You can list filesystem source paths relative to the Calamares run
 # directory, if you use -d (this is only useful for testing, though).
+#
 #    -   source: ./example.sqfs
 #        sourcefs: squashfs
 #        destination: ""
-# You can list individual files
+#
+# You can list individual files (copied one-by-one), or directories
+# (the files inside this directory are copied directly to the destination,
+# so no "dummycpp/" subdirectory is created in this example).
+# Do note that the target directory must exist already (e.g. from
+# extracting some other filesystem).
+#
+#    -   source: ../CHANGES
+#        sourcefs: file
+#        destination: "/tmp/derp"
+#    -   source: ../src/modules/dummycpp
+#        sourcefs: file
+#        destination: "/tmp/derp"
+
+unpack:
     -   source: ../CHANGES
         sourcefs: file
-        destination: "/tmp/derp"
-# .. or directories
-    -   source: ../src/modules/dummycpp
-        sourcefs: file
-        destination: "/tmp/derp"
+        destination: "/tmp"