[quant][fx][improvement] Renamed default_affine_fixed_qparams_observer and default_symmetric_fixed_qparams_observer (#76637)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/76637
The previous naming convention `default_affine_fixed_qparams_observer`
and `default_symmetric_fixed_qparams_observer` were uninformative, and users had to read
the definition in order to understand what these observers are. The new
naming convention reveals information about the range of the observers
The analogous changes were also made for
`default_symmetric_fixed_qparams_fake_quant` and
`default_affine_fixed_qparams_fake_quant`
Test Plan:
```
python test/test_quantization.py
```
```
python test/test_quantization.py
```
Differential Revision:
D36054169
D36054169
Reviewed By: vkuzo
Pulled By: dzdang
fbshipit-source-id: 215f7786a4b7abda7327f17cc61735697ec5cca9
(cherry picked from commit 21a4e6eda4467c8adca7fd534a506a14e975f9cf)
