Fixed documentation.

Author: alkhwarizmi

README.rst

@@ -39,7 +39,7 @@ Install the version as packaged with your OpenModelica installation by running::
   cd %OPENMODELICAHOME%\share\omc\scripts\PythonInterface
   python -m pip install -U .
 
-Instead, to Install the latest version of the OMPython master tree only, previously cloned into <OMPythonPath>, run::
+Instead, to Install the latest version of the OMPython master branch only, previously cloned into ``<OMPythonPath>``, run::
 
   cd <OMPythonPath>
   python -m pip install -U .