BUG: Fix a fatal error preventing documentation generation in some ca…

…ses (#302)

* Update __init__.py

Got a fatal exception on this line, which prevented the generation of the documentation.

The problem is that some variable is initialized in a try bloc but still used out of it afterwards.
If the getattr fails line 682 - which was my problem - then the variable is used without being initialized, which lead to fatal error.

* Use `try-else` block

pdoc/__init__.py

@@ -686,9 +686,10 @@ def __init__(self, module: Union[ModuleType, str], *,
                 except AttributeError:
                     warn(f"Module {self.module!r} doesn't contain identifier `{name}` "
                          "exported in `__all__`")
-                if not _is_blacklisted(name, self):
-                    obj = inspect.unwrap(obj)
-                public_objs.append((name, obj))
+                else:
+                    if not _is_blacklisted(name, self):
+                        obj = inspect.unwrap(obj)
+                    public_objs.append((name, obj))
         else:
             def is_from_this_module(obj):
                 mod = inspect.getmodule(inspect.unwrap(obj))