Remove extra colon

Author: rhpvorderman

README.rst

@@ -47,16 +47,16 @@ Installation
 ------------
 Installation with pip
 .....................
-Python-isal can be installed with:::
+Python-isal can be installed with::
 
     pip install isal
 
 This will include a staticallly linked version of isa-l. If you wish to link
-dynamically against a version of libisal installed on your system use:::
+dynamically against a version of libisal installed on your system use::
 
      PYTHON_ISAL_LINK_DYNAMIC=true pip install isal
 
-The latest development version of python-isal can be installed with:::
+The latest development version of python-isal can be installed with::
 
     pip install git+https://github.com/rhpvorderman/python-isal.git