CLN: Incorrect name in docstrings for generic
E.g. for reindex on panel

```
elp on method reindex in module pandas.core.generic:

reindex(self, *args, **kwargs) method of pandas.core.panel.Panel instance
    Conform DataFrame to new index with optional filling logic, placing
    NA/NaN in locations having no value in the previous index. A new object
    is produced unless the new index is equivalent to the current one and
    copy=False

    Parameters
    ----------
    axes : array-like, optional (can be specified in order, or as keywords)
        New labels / index to conform to. Preferably an Index object to
        avoid duplicating data
    method : {'backfill', 'bfill', 'pad', 'ffill', None}, default None
        Method to use for filling holes in reindexed DataFrame
        pad / ffill: propagate last valid observation forward to next valid
        backfill / bfill: use NEXT valid observation to fill gap
    copy : boolean, default True
        Return a new object, even if the passed indexes are the same
    level : int or name
        Broadcast across a level, matching Index values on the
        passed MultiIndex level
    fill_value : scalar, default np.NaN
        Value to use for missing values. Defaults to NaN, but can be any
        "compatible" value
    limit : int, default None
        Maximum size gap to forward or backward fill
    takeable : boolean, default False
        treat the passed as positional values

    Examples
    --------
```

Functions that need parameters list/explanation:
- [x] swapaxes
- [x] pop [what does 'items' mean?]

Functions that only need list of axes:
- [x] filter [need to check if it should be defined for Series at all]
- [x] fillna [Series, Frame]
- [x] reindex_axis [needs class name + axes]
- [x] rename [might need a bit more logic to do docstring + note that args interpreted like axes??]
- [x] transpose

Functions needing a little work:
- [x] reindex
  - needs to have panel check that both major and major_axis aren't passed, same with minor and minor_axis (like `SparsePanel` does)
  - would be better if there were individual functions for Series Frame and Panel that explicitly enumerate axes in type signature.

Functions that may not need to be changed:
- [x] align

Functions that could use slight wording tweaks:
- [x] truncate
- [x] where
- [x] mask
