MNT: update vendored docs script github_link.py (#3144)

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## Changes proposed in this pull request

As far as I can see, we had just added a few lines to tell this vendored
script originates in scikit-learn.
    
File initially copied in #1258, and [not changed
since](https://github.com/nipreps/fmriprep/commits/master/docs/sphinxext/github_link.py),
except for #3097 which I shouldn't have applied to a vendored file.

Author: effigies

docs/sphinxext/github_link.py

@@ -1,24 +1,24 @@
 """
-This script comes from scikit-learn:
+This vendored script comes from scikit-learn:
 https://github.com/scikit-learn/scikit-learn/blob/master/doc/sphinxext/github_link.py
 """
-from operator import attrgetter
 import inspect
-import subprocess
 import os
+import subprocess
 import sys
 from functools import partial
+from operator import attrgetter
 
-REVISION_CMD = 'git rev-parse --short HEAD'
+REVISION_CMD = "git rev-parse --short HEAD"
 
 
 def _get_git_revision():
     try:
         revision = subprocess.check_output(REVISION_CMD.split()).strip()
     except (subprocess.CalledProcessError, OSError):
-        print('Failed to execute git to get revision')
+        print("Failed to execute git to get revision")
         return None
-    return revision.decode('utf-8')
+    return revision.decode("utf-8")
 
 
 def _linkcode_resolve(domain, info, package, url_fmt, revision):
@@ -30,25 +30,26 @@ def _linkcode_resolve(domain, info, package, url_fmt, revision):
     >>> _linkcode_resolve('py', {'module': 'tty',
     ...                          'fullname': 'setraw'},
     ...                   package='tty',
-    ...                   url_fmt='https://hg.python.org/cpython/file/'
+    ...                   url_fmt='http://hg.python.org/cpython/file/'
     ...                           '{revision}/Lib/{package}/{path}#L{lineno}',
     ...                   revision='xxxx')
-    'https://hg.python.org/cpython/file/xxxx/Lib/tty/tty.py#L18'
+    'http://hg.python.org/cpython/file/xxxx/Lib/tty/tty.py#L18'
     """
 
     if revision is None:
         return
-    if domain not in ('py', 'pyx'):
+    if domain not in ("py", "pyx"):
         return
-    if not info.get('module') or not info.get('fullname'):
+    if not info.get("module") or not info.get("fullname"):
         return
 
-    class_name = info['fullname'].split('.')[0]
-    if type(class_name) != str:
-        # Python 2 only
-        class_name = class_name.encode('utf-8')
-    module = __import__(info['module'], fromlist=[class_name])
-    obj = attrgetter(info['fullname'])(module)
+    class_name = info["fullname"].split(".")[0]
+    module = __import__(info["module"], fromlist=[class_name])
+    obj = attrgetter(info["fullname"])(module)
+
+    # Unwrap the object to get the correct source
+    # file in case that is wrapped by a decorator
+    obj = inspect.unwrap(obj)
 
     try:
         fn = inspect.getsourcefile(obj)
@@ -62,14 +63,12 @@ def _linkcode_resolve(domain, info, package, url_fmt, revision):
     if not fn:
         return
 
-    fn = os.path.relpath(fn,
-                         start=os.path.dirname(__import__(package).__file__))
+    fn = os.path.relpath(fn, start=os.path.dirname(__import__(package).__file__))
     try:
         lineno = inspect.getsourcelines(obj)[1]
     except Exception:
-        lineno = ''
-    return url_fmt.format(revision=revision, package=package,
-                          path=fn, lineno=lineno)
+        lineno = ""
+    return url_fmt.format(revision=revision, package=package, path=fn, lineno=lineno)
 
 
 def make_linkcode_resolve(package, url_fmt):
@@ -84,5 +83,6 @@ def make_linkcode_resolve(package, url_fmt):
                                    '{path}#L{lineno}')
     """
     revision = _get_git_revision()
-    return partial(_linkcode_resolve, revision=revision, package=package,
-                   url_fmt=url_fmt)
+    return partial(
+        _linkcode_resolve, revision=revision, package=package, url_fmt=url_fmt
+    )