FIX: Typing annotations

Running `mypy -p IPython.sphinxext` raised a few errors. Fix them and
strip some trailing whitespace from a few places.

IPython/sphinxext/custom_doctests.py

@@ -107,7 +107,7 b' def float_doctest(sphinx_shell, args, input_lines, found, submitted):'
         try:
             rtol = float(args[2])
             atol = float(args[3])
-        except IndexError as e:
+        except IndexError:
             e = ("Both `rtol` and `atol` must be specified "
                  "if either are specified: {0}".format(args))
             raise IndexError(e) from e

IPython/sphinxext/ipython_directive.py

@@ -174,7 +174,7 b' To Do'
 
 # Authors
 # =======
-# 
+#
 # - John D Hunter: original author.
 # - Fernando Perez: refactoring, documentation, cleanups, port to 0.11.
 # - VáclavŠmilauer <eudoxos-AT-arcig.cz>: Prompt generalizations.
@@ -196,6 +196,7 b' import ast'
 import warnings
 import shutil
 from io import StringIO
+from typing import Any, Dict, Set
 
 # Third-party
 from docutils.parsers.rst import directives
@@ -425,7 +426,7 b' class EmbeddedSphinxShell(object):'
         source_dir = self.source_dir
         saveargs = decorator.split(' ')
         filename = saveargs[1]
-        # insert relative path to image file in source 
+        # insert relative path to image file in source
         # as absolute path for Sphinx
         # sphinx expects a posix path, even on Windows
         path = pathlib.Path(savefig_dir, filename)
@@ -901,11 +902,11 b' class EmbeddedSphinxShell(object):'
 
 class IPythonDirective(Directive):
 
-    has_content = True
-    required_arguments = 0
-    optional_arguments = 4 # python, suppress, verbatim, doctest
-    final_argumuent_whitespace = True
-    option_spec = { 'python': directives.unchanged,
+    has_content: bool = True
+    required_arguments: int = 0
+    optional_arguments: int = 4 # python, suppress, verbatim, doctest
+    final_argumuent_whitespace: bool = True
+    option_spec: Dict[str, Any] = { 'python': directives.unchanged,
                     'suppress' : directives.flag,
                     'verbatim' : directives.flag,
                     'doctest' : directives.flag,
@@ -915,7 +916,7 b' class IPythonDirective(Directive):'
 
     shell = None
 
-    seen_docs = set()
+    seen_docs: Set = set()
 
     def get_config_options(self):
         # contains sphinx configuration variables