Omit extra space in Sphinx auto-attribute comments

This feature of Sphinx is described in:
http://www.sphinx-doc.org/en/stable/ext/autodoc.html#directive-autoattribute

Fixes #68

README.md

@@ -324,6 +324,9 @@ More details can be found in [CONTRIBUTING](CONTRIBUTING.md).
 
 * omit extra space in kwarg unpacking if it's the first argument (#46)
 
+* omit extra space in [Sphinx auto-attribute comments](http://www.sphinx-doc.org/en/stable/ext/autodoc.html#directive-autoattribute)
+  (#68)
+
 
 ### 18.3a3
 

black.py

@@ -1183,7 +1183,7 @@ def make_comment(content: str) -> str:
 
     if content[0] == '#':
         content = content[1:]
-    if content and content[0] not in {' ', '!', '#'}:
+    if content and content[0] not in ' !:#':
         content = ' ' + content
     return '#' + content
 

tests/comments.py

@@ -49,6 +49,26 @@ def function(default=None):
 # This time two lines.
 
 
+class Foo:
+    """Docstring for class Foo.  Example from Sphinx docs."""
+
+    #: Doc comment for class attribute Foo.bar.
+    #: It can have multiple lines.
+    bar = 1
+
+    flox = 1.5  #: Doc comment for Foo.flox. One line only.
+
+    baz = 2
+    """Docstring for class attribute Foo.baz."""
+
+    def __init__(self):
+        #: Doc comment for instance attribute qux.
+        self.qux = 3
+
+        self.spam = 4
+        """Docstring for instance attribute spam."""
+
+
 @fast(really=True)
 async def wat():
     async with X.open_async() as x:  # Some more comments