Minor fixes to user guide

docs-source/usersguide/application.rst

@@ -1021,13 +1021,15 @@ mass constant while slowing down the fast motions of hydrogens.  When combined
 with constraints (typically :code:`constraints=AllBonds`\ ), this often allows a
 further increase in integration step size.
 
+.. _integrators:
+
 Integrators
 ===========
 
 
 OpenMM offers a choice of several different integration methods.  You select
 which one to use by creating an integrator object of the appropriate type.
-Detailed descriptions of all these integrators can be found in Section
+Detailed descriptions of all these integrators can be found in Chapter
 :ref:`integrators-theory`.  In addition to these built in integrators, lots of
 others are available as part of the `OpenMMTools <https://openmmtools.readthedocs.io>`_ package.
 

docs-source/usersguide/theory.rst

@@ -1379,9 +1379,8 @@ are updated as follows:
    \mathbf{r}_{i}(t+\Delta t) = \mathbf{r}_{i}(t+\Delta t/2) + \mathbf{v'}_{i}(t+\Delta t/2)\Delta t/2
 
 
-This tends to produce more accurate
-sampling of configurational properties (such as free energies), but less
-accurate sampling of kinetic properties (such as mean kinetic energy).  Because
+This tends to produce more accurate sampling of configurational properties (such
+as free energies), but less accurate sampling of kinetic properties.  Because
 configurational properties are much more important than kinetic ones in most
 simulations, this integrator is generally preferred over LangevinIntegrator.  It
 often allows one to use a larger time step while still maintaining similar or