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 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

@@ -196,6 +196,7 import ast
 import warnings
 import shutil
 from io import StringIO
+from typing import Any, Dict, Set
 
 # Third-party
 from docutils.parsers.rst import directives
@@ -901,11 +902,11 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 class IPythonDirective(Directive):
 
     shell = None
 
-    seen_docs = set()
+    seen_docs: Set = set()
 
     def get_config_options(self):
         # contains sphinx configuration variables