Document element name lookup in MjSpec.

PiperOrigin-RevId: 725258206
Change-Id: I5c9a85d25787eb38e9e8c3854eda2581700e188e

doc/python.rst

@@ -587,14 +587,19 @@ Convenience methods
 The Python bindings provide a number of convenience methods and attributes not directly available in the C API in order
 to make model editing easier:
 
+Finding elements
+^^^^^^^^^^^^^^^^
+The ``MjSpec`` object has methods like ``find_body(), find_joint(), find_site(), ...`` for every type of name-able
+:ref:`mjtObj` type. These methods take a name string and return the element with that name or ``None`` if it does not
+exist.
+
 Element lists
 ^^^^^^^^^^^^^
 Lists of all elements in a spec can be accessed using named properties, using the plural form. For example,
-``spec.meshes`` returns a list of all meshes in the spec.
-
-The following properties are implemented: ``sites``, ``geoms``, ``joints``, ``lights``, ``cameras``, ``bodies``,
-``frames``, ``materials``, ``meshes``, ``pairs``, ``equalities``, ``tendons``, ``actuators``, ``skins``, ``textures``,
-``texts``, ``tuples``, ``flexes``, ``hfields``, ``keys``, ``numerics``, ``excludes``, ``sensors``, ``plugins``.
+``spec.meshes`` returns a list of all meshes in the spec. The following properties are implemented: ``sites``,
+``geoms``, ``joints``, ``lights``, ``cameras``, ``bodies``, ``frames``, ``materials``, ``meshes``, ``pairs``,
+``equalities``, ``tendons``, ``actuators``, ``skins``, ``textures``, ``texts``, ``tuples``, ``flexes``, ``hfields``,
+``keys``, ``numerics``, ``excludes``, ``sensors``, ``plugins``.
 
 Tree traversal
 ^^^^^^^^^^^^^^
@@ -611,8 +616,9 @@ Recursive search:
   ``body.find_all(mujoco.mjtObj.mjOBJ_SITE)`` or ``body.find_all('site')`` will return a list of all sites under the
   body.
 
-Additionally, the parent body of a given element - including bodies and frames - can be accessed via the ``parent``
-property. For example, the parent of a site can be accessed via ``site.parent``.
+Parent:
+  The parent body of a given element -- including bodies and frames -- can be accessed via the ``parent`` property.
+  For example, the parent of a site can be accessed via ``site.parent``.
 
 Relationship to ``PyMJCF``
 --------------------------