Do not mix up external tools for updating and for packaging

Explicitely tell the difference between external tools for updating and for packaging

Author: iTrooz

source/packaging-guide/optional/updates.rst

@@ -26,8 +26,8 @@ Currently, there is only one backend available to update AppImages : `ZSync2 <ht
 
 
 
-Using appimagetool
-^^^^^^^^^^^^^^^^^^
+If packaged with appimagetool
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Use :code:`appimagetool -u` to embed update information (as specified in the AppImageSpec) and generate the corresponding :code:`.zsync` file you can upload to the place mentioned in the update information.
 
@@ -47,22 +47,22 @@ is called the *update information*.
 Please see https://github.com/AppImage/AppImageSpec/blob/master/draft.md#update-information for a description of allowable types of update information.
 
 
-Using linuxdeploy
-^^^^^^^^^^^^^^^^^
+If packaged with linuxdeploy
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 :ref:`linuxdeploy's <ref-linuxdeploy>` `AppImage plugin <https://github.com/linuxdeploy/linuxdeploy-plugin-appimage>`__ supports an environment variable ``$UPDATE_INFORMATION`` (or short ``$UPD_INFO``) that can be used to set the update information manually.
 
 Please see `the README <https://github.com/linuxdeploy/linuxdeploy-plugin-appimage#optional-variables>`__ for details.
 
 
-Using linuxdeployqt
-^^^^^^^^^^^^^^^^^^^
+If packaged with linuxdeployqt
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 :code:`linuxdeployqt` uses :code:`appimagetool` internally. If it recognizes that it is running on Travis CI, then it automatically generates the matching update information.
 
 
-Using electron-builder
-^^^^^^^^^^^^^^^^^^^^^^
+If packaged with electron-builder
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 :code:`electron-builder` promotes its own updater scheme rather than the update information described in this documentation, in order to have the same mechanism on Linux as is used on Windows. Unfortunately this means that AppImages generated by :code:`electron-builder` cannot be updated using the usual tools.