docs: add 'Inspector'

docs/level_editor/index.rst

@@ -16,5 +16,6 @@ Console.
 	level_editor
 	project_browser
 	console
+	inspector
 	level_viewport
 	texture_settings

docs/level_editor/inspector.rst

@@ -0,0 +1,40 @@
+=========
+Inspector
+=========
+
+The Inspector lets you view and modify the properties of selected objects in
+the :ref:`Level Viewport`. Select one or more objects to display their
+components and editable fields. Changes made in the Inspector are applied
+immediately and reflected in the Level Viewport.
+
+.. figure:: images/inspector.png
+   :align: center
+
+   The Inspector showing the properties of a Unit.
+
+Expression evaluator
+====================
+
+Numeric entries in the Inspector can evaluate simple mathematical expressions,
+which is handy for precise adjustments. Type an expression and press
+``Enter`` to evaluate it. The special variable ``x`` represents the current
+value in the field. For example, if a field contains ``2``, entering ``x +
+1`` changes it to ``3``.
+
+.. figure:: images/inspector_entry_expression.png
+   :align: center
+
+   A simple expression in a numeric entry.
+
+Revealing resources
+===================
+
+Properties that reference resources include a ``Reveal`` shortcut that opens
+the :ref:`Project Browser` and highlights the referenced resource. The reveal
+action attempts to locate the resource even when the resource type is hidden
+or when the file resides in a mapped source directory that is not shown.
+
+.. figure:: images/inspector_reveal_resource.svg
+   :align: center
+
+   The ``Reveal`` button.

docs/level_editor/level_editor.rst

@@ -17,7 +17,7 @@ Number Name                    What it shows
 ====== ======================= =============
 1      :ref:`Project Browser`  The current project's contents.
 2      :ref:`Console`          Messages from the Level Editor, the Game and other Runtimes.
-3      Inspector               The properties of the currently selected object.
+3      :ref:`Inspector`        The properties of the currently selected object.
 4      Level Tree              A hierarchical view of all the objects in the Level.
 5      :ref:`Level Viewport`   The Level being edited.
 6      Menubar                 Common commands for editing / debugging / opening editors etc.