'annotate' ignores path_effects argument.

With current master, `annotate` ignores `path_effects` argument.

```python
import matplotlib.pyplot as plt
from matplotlib.patheffects import withStroke
myeffect = withStroke(foreground="y", linewidth=3)
kwargs = dict(path_effects=[myeffect])

plt.annotate("test", (0.5, 0.5), path_effects=[myeffect])
```

text is drawn, but without path_effects.