Update notes on optional arguments [av skip]

Author: daanhb

doc/manual/functions.rst

@@ -448,7 +448,7 @@ specified:
 
 Optional arguments are actually just a convenient syntax for writing
 multiple method definitions with different numbers of arguments
-(see :ref:`man-note-on-optinal-and-keyword-arguments`).
+(see :ref:`man-note-on-optional-and-keyword-arguments`).
 
 
 Keyword Arguments

doc/manual/methods.rst

@@ -523,7 +523,7 @@ can also constrain type parameters of methods::
 The ``same_type_numeric`` function behaves much like the ``same_type``
 function defined above, but is only defined for pairs of numbers.
 
-.. _man-Note-on-optional-and-keyword-arguments:
+.. _man-note-on-optional-and-keyword-arguments:
 
 Note on Optional and keyword Arguments
 --------------------------------------