Fix some broken refs in the docs.

INSTALL.rst

@@ -90,10 +90,9 @@ the latest *tar.gz* release file from `the PyPI files page
 develop Matplotlib or just need the latest bugfixed version, grab the
 latest git version, and see :ref:`install-from-git`.
 
-The standard environment variables `CC`, `CXX`, `PKG_CONFIG` are respected.
-This means you can set them if your toolchain is prefixed. This may be used for
-cross compiling.
-::
+The standard environment variables :envvar:`CC`, :envvar:`CXX`,
+:envvar:`PKG_CONFIG` are respected.  This means you can set them if your
+toolchain is prefixed. This may be used for cross compiling. ::
 
   export CC=x86_64-pc-linux-gnu-gcc
   export CXX=x86_64-pc-linux-gnu-g++
@@ -203,9 +202,9 @@ etc., you can install the following:
 
   The following libraries are shipped with Matplotlib:
 
-  - `Agg`: the Anti-Grain Geometry C++ rendering engine;
-  - `qhull`: to compute Delaunay triangulation;
-  - `ttconv`: a TrueType font utility.
+  - ``Agg``: the Anti-Grain Geometry C++ rendering engine;
+  - ``qhull``: to compute Delaunay triangulation;
+  - ``ttconv``: a TrueType font utility.
 
 .. _build_linux:
 

doc/users/prev_whats_new/whats_new_1.5.rst

@@ -734,9 +734,9 @@ IPython's ``HTML`` display class::
 Prefixed pkg-config for building
 --------------------------------
 
-Handling of `pkg-config` has been fixed in so far as it is now
-possible to set it using the environment variable `PKG_CONFIG`. This
-is important if your toolchain is prefixed. This is done in a simpilar
-way as setting `CC` or `CXX` before building. An example follows.
+Handling of pkg-config has been fixed in so far as it is now possible to set it
+using the environment variable :envvar:`PKG_CONFIG`. This is important if your
+toolchain is prefixed. This is done in a simpilar way as setting :envvar:`CC`
+or :envvar:`CXX` before building. An example follows.
 
     export PKG_CONFIG=x86_64-pc-linux-gnu-pkg-config