enable invocation of run_ner.py and utils_ner.py in cython
Due to extant issue https://github.com/cython/cython/issues/2903, `run_ner.py` and `utils_ner.py` (among others, I imagine) cannot be invoked inside Cython. By manually adding in annotations, these changes work around the missing features in Cython 3.7 re: PEP557.
https://github.com/cython/cython/pull/3400 ought to eventually fix the underlying issue.

I'm offering code here that works around this behavior in case it would be helpful to others.
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/4917?src=pr&el=h1) Report
> Merging [#4917](https://codecov.io/gh/huggingface/transformers/pull/4917?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/ef2dcdccaa9a115aca44d81f31c6dc4d32bebb3f&el=desc) will **increase** coverage by `0.00%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/4917/graphs/tree.svg?width=650&height=150&src=pr&token=9qOlN6Hb1c)](https://codecov.io/gh/huggingface/transformers/pull/4917?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master    #4917   +/-   ##
=======================================
  Coverage   77.12%   77.13%           
=======================================
  Files         128      128           
  Lines       21650    21650           
=======================================
+ Hits        16698    16700    +2     
+ Misses       4952     4950    -2     
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/4917?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/file\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/4917/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9maWxlX3V0aWxzLnB5) | `73.09% <0.00%> (-0.41%)` | :arrow_down: |
| [src/transformers/modeling\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/4917/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ191dGlscy5weQ==) | `90.61% <0.00%> (+0.11%)` | :arrow_up: |
| [src/transformers/modeling\_tf\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/4917/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl91dGlscy5weQ==) | `87.57% <0.00%> (+0.31%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/4917?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/4917?src=pr&el=footer). Last update [ef2dcdc...74e1e66](https://codecov.io/gh/huggingface/transformers/pull/4917?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
<|||||>This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
