LineCollection.contains (ab)uses pickradius<=0 as marker for "filled"

まだ誰も着手していません。

### Bug report

**Bug summary**

When the pickradius of a LineCollection is set to a <=0 value, LineCollection.contains treats the polygon as "closed".

**Code for reproduction**
```python
from matplotlib import pyplot as plt
from matplotlib.collections import LineCollection
from matplotlib.backend_bases import MouseEvent
import numpy as np

fig, axs = plt.subplots(2)

for ax, pr in zip(axs, [0, 10]):
coll = LineCollection([[(0, 0), (1, 0), (0, 1)]])
ax.add_collection(coll)
ax.set(xlim=(-1, 2), ylim=(-1, 2))
coll.set_pickradius(pr)
for x in np.linspace(*ax.get_xlim())[1:-1]:
for y in np.linspace(*ax.get_ylim())[1:-1]:
x1, y1 = ax.transData.transform((x, y))
contained, _ = coll.contains(
MouseEvent("button_press_event", fig.canvas, x1, y1))
ax.plot(x, y, "o", c="g" if contained else "r", ms=1)

plt.show()
```
**Actual outcome**


Note how on the top LineCollection (using pickradius=0), all points "in" the closed polygon are considered "contained".

**Expected outcome**

Only points exactly on the LineCollection are contained for pickradius = 0, no points are contained for pickradius < 0 (consistently with Line2D).

---

The relevant code is in Line2D.contains:
```python
ind = _path.point_in_path_collection(
mouseevent.x, mouseevent.y, pickradius,
transform.frozen(), paths, self.get_transforms(),
offsets, transOffset, pickradius <= 0, # <--- this last argument is "filled"
self._offset_position)
```

**Matplotlib version**

* Operating system: linux
* Matplotlib version: master, likely since a long time ago
* Matplotlib backend (`print(matplotlib.get_backend())`): any
* Python version: 38
* Jupyter version (if applicable): no
* Other libraries: no

LineCollection.contains から始め、Line2D.contains との動作を比較します。特に、レポートに示されている _path.point_in_path_collection の呼び出しを確認してください。提供されている再現コードを pickradius の値 0、10、0 未満で実行し、それぞれの値について包含が記載された期待される動作と一致することを確認してください。

索引モデルが issue の本文から書いたものです。