Use inspect.cleandoc in autogen_config.

... instead of a custom implementation of the same thing.

docs/autogen_config.py

@@ -1,6 +1,7 b''
 #!/usr/bin/env python
 
 from os.path import join, dirname, abspath
+import inspect
 
 from IPython.terminal.ipapp import TerminalIPythonApp
 from ipykernel.kernelapp import IPKernelApp
@@ -14,33 +15,6 b" generated = join(options, 'config-generated.txt')"
 import textwrap
 indent = lambda text,n: textwrap.indent(text,n*' ')
 
-def dedent(text):
-    """Equivalent of textwrap.dedent that ignores unindented first line.
-
-    This means it will still dedent strings like:
-    '''foo
-    is a bar
-    '''
-
-    For use in wrap_paragraphs.
-    """
-
-    if text.startswith('\n'):
-        # text starts with blank line, don't ignore the first line
-        return textwrap.dedent(text)
-
-    # split first line
-    splits = text.split('\n',1)
-    if len(splits) == 1:
-        # only one line
-        return textwrap.dedent(text)
-
-    first, rest = splits
-    # dedent everything but the first line
-    rest = textwrap.dedent(rest)
-    return '\n'.join([first, rest])
-
-
 
 def interesting_default_value(dv):
     if (dv is None) or (dv is Undefined):
@@ -72,7 +46,7 b' def class_config_rst_doc(cls, trait_aliases):'
                  ]
 
         help = trait.help.rstrip() or 'No description'
-        lines.append(indent(dedent(help), 4) + '\n')
+        lines.append(indent(inspect.cleandoc(help), 4) + '\n')
 
         # Choices or type
         if 'Enum' in ttype: