Small docs fixes

Author: spookylukey

docs/history.rst

@@ -9,7 +9,7 @@ History and release notes
 
 * Dropped support for Python < 3.6
 * Added :meth:`Parser.until`. Thanks `@mcdeoliveira <https://github.com/mcdeoliveira>`_!
-* `Parser.optional` now supports an optional default argument to be returned instead of ``None``.
+* :meth:`Parser.optional` now supports an optional default argument to be returned instead of ``None``.
 
 1.4.0 - 2021-11-15
 ------------------

docs/ref/methods_and_combinators.rst

@@ -130,7 +130,7 @@ can be used and manipulated as below.
 
    .. versionadded:: 2.0
 
-   .. method:: optional([default=None])
+   .. method:: optional(default=None)
 
       Returns a parser that expects the initial parser zero or once, and maps
       the result to a given default value in the case of no match. If no default