DOC: tidy 1.1.5 release notes
test failure unrelated

```
=========================== short test summary info ============================
FAILED pandas/tests/plotting/frame/test_frame.py::TestDataFramePlots::test_area_lim
= 1 failed, 143863 passed, 3150 skipped, 1421 xfailed, 31 warnings in 2993.64s (0:49:53) =
```