[doc] Update example descriptions

Author: stephane-caron

examples/load_in_pinocchio.py

@@ -17,6 +17,8 @@
 
 """
 Load a robot description, specified from the command line, in Pinocchio.
+
+This example requires Pinocchio, which is installed by ``pip install pin``.
 """
 
 import argparse

examples/load_in_pybullet.py

@@ -18,8 +18,7 @@
 """
 Show a robot descriptions specified from the command line, using yourdfpy.
 
-This tool requires PyBullet. It can be installed separately (``pip install
-pybullet``).
+This example requires PyBullet, which is installed by ``pip install pybullet``.
 """
 
 import argparse

examples/show_in_meshcat.py

@@ -17,6 +17,9 @@
 
 """
 Show a robot descriptions specified from the command line, using MeshCat.
+
+This example requires Pinocchio, which is installed by ``pip install pin``, and
+MeshCat, which is installed by ``pip install meshcat``.
 """
 
 import argparse

examples/show_in_pybullet.py

@@ -18,8 +18,7 @@
 """
 Show a robot descriptions specified from the command line, using yourdfpy.
 
-This tool requires PyBullet. It can be installed separately (``pip install
-pybullet``).
+This example requires PyBullet, which is installed by ``pip install pybullet``.
 """
 
 import argparse

examples/show_in_yourdfpy.py

@@ -23,7 +23,7 @@
     implementation, including the ability to set the robot configuration or
     show collision meshes.
 
-This tool requires `yourdfpy` which is an optional dependency. It can be
+This example requires `yourdfpy` which is an optional dependency. It can be
 installed separately (``pip install yourdfpy``), or when robot descriptions are
 installed via ``pip install robot_descriptions[cli]``.
 """