Make Note usage consistent in adapter_mixins.py
Inconsistent usage of the word Note, which includes a broken reading in one case.

I'm just doing some tidying -- not trying to be critical.

**Before**:

![image](https://github.com/NVIDIA/NeMo/assets/7584774/efceb708-a2fe-46e6-aeed-29b43e988fa0)

**After**:
![image](https://github.com/NVIDIA/NeMo/assets/7584774/8a697ba3-ad4d-42db-8616-f5cf5fd407d5)

**Collection**: NeMo Core (documentation)

# Changelog 
- I changed the inconsistent use of the word Note: in documentation to `.. note:: ` as used elsewhere

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- [x] Did you write any new necessary tests? (no tests needed -- documentation fix)
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- [ ] Bugfix
- [x] Documentation

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# Additional Information
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