doc: note that libinput measure is a separate package

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

doc/user/touchpad-pressure-debugging.rst

@@ -27,6 +27,9 @@ required for a touchpad device and how to add the required
 change at any time**. Users are advised to :ref:`report a bug <reporting_bugs>`
 with the updated pressure ranges when testing has completed.
 
+.. note:: Most distributions ship ``libinput measure`` in a separate
+	``libinput-utils`` package.
+
 Use the ``libinput measure touchpad-pressure`` tool provided by libinput.
 This tool will search for your touchpad device and print some pressure
 statistics, including whether a touch is/was considered logically down.
@@ -124,6 +127,9 @@ required for a touchpad device and how to add the required
 change at any time**. Users are advised to :ref:`report a bug <reporting_bugs>`
 with the updated pressure ranges when testing has completed.
 
+.. note:: Most distributions ship ``libinput measure`` in a separate
+	``libinput-utils`` package.
+
 Use the ``libinput measure touch-size`` tool provided by libinput.
 This tool will search for your touchpad device and print some touch size
 statistics, including whether a touch is/was considered logically down.