DOC: Single backticks when referring to parameters in documentation

Author: pauldmccarthy

nibabel/nifti1.py

@@ -1768,12 +1768,12 @@ def __init__(self, dataobj, affine, header=None,
     Notes
     -----
 
-    If both a ``header`` and an ``affine`` are specified, and the ``affine``
-    does not match the affine that is in the ``header``, the ``affine`` will
-    be used, but the ``sform_code`` and ``qform_code`` fields in the header
-    will be re-initialised to their default values. This is performed on the
-    basis that, if you are changing the affine, you are likely to be changing
-    the space to which the affine is pointing.  The :meth:`set_sform` and
+    If both a `header` and an `affine` are specified, and the `affine` does
+    not match the affine that is in the `header`, the `affine` will be used,
+    but the ``sform_code`` and ``qform_code`` fields in the header will be
+    re-initialised to their default values. This is performed on the basis
+    that, if you are changing the affine, you are likely to be changing the
+    space to which the affine is pointing.  The :meth:`set_sform` and
     :meth:`set_qform` methods can be used to update the codes after an image
     has been created - see those methods, and the :ref:`manual
     <default-sform-qform-codes>` for more details.  '''