Fix formatting on RTD

Author: njsmith

doc/changes.rst

@@ -98,7 +98,6 @@ v0.2.1
 .. image:: https://zenodo.org/badge/doi/10.5281/zenodo.11447.png
    :target: http://dx.doi.org/10.5281/zenodo.11447
 
-|
 * Fixed a nasty bug in missing value handling where, if missing values
   were present, ``dmatrix(..., result_type="dataframe")`` would always
   crash, and ``dmatrices("y ~ 1")`` would produce left- and right-hand
@@ -117,7 +116,6 @@ v0.2.0
 .. image:: https://zenodo.org/badge/doi/10.5281/zenodo.11448.png
    :target: http://dx.doi.org/10.5281/zenodo.11448
 
-|
 Warnings:
 
 * The lowest officially supported Python version is now 2.5. So far as
@@ -154,5 +152,4 @@ v0.1.0
 .. image:: https://zenodo.org/badge/doi/10.5281/zenodo.11449.png
    :target: http://dx.doi.org/10.5281/zenodo.11449
 
-|
 First public release.