BUG: allow use of both default+input resolvers in df.eval, GH34966
- [x] closes #34966
- [x] tests added / passed (all tests passed except those which were auto-cancelled for taking too long)
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit) for how to run them
- [x] whatsnew entry

Allows default resolvers to be used with input resolvers in `pandas.dataframe.eval`. Previously cases such as this would break:
```python
import pandas as pd

df = pd.DataFrame({'a':[0,1,2], 'b':[7,8,9]}) 
d = {'c': 5}
df.eval('a+b*c', resolvers=[d])
```
with `pandas.core.computation.ops.UndefinedVariableError: name 'a' is not defined` as explained in #34966. Following this update, the above works as expected.
Added a test similar to the above: `tests.frame.test_query_eval.TestDataFrameEval.test_eval_resolvers_combined`
Hello @bubblingoak! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:





There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2022-01-04 00:39:55 UTC > umm can you add a test which fails w/o this change

Added the test `tests.frame.test_query_eval.TestDataFrameEval.test_eval_resolvers_combined`. The updated code passes, but current master fails on [line 174](https://github.com/bubblingoak/pandas/blob/fix-df-eval-resolvers/pandas/tests/frame/test_query_eval.py#L174): 
```python
result = df.eval("a + b * c", resolvers=[dict1])
```
with `pandas.core.computation.ops.UndefinedVariableError: name 'a' is not defined` thanks @bubblingoak 