Add relu operator

[stever178]

pytest output:

=============================== test session starts ================================
platform linux -- Python 3.12.3, pytest-8.3.5, pluggy-1.5.0
rootdir: /home/lsj/projects/ntops
configfile: pyproject.toml
plugins: cov-6.1.1
collected 70 items

tests/test_abs.py ........                                                   [ 11%]
tests/test_add.py ........                                                   [ 22%]
tests/test_addmm.py ..                                                       [ 25%]
tests/test_bmm.py ..                                                         [ 28%]
tests/test_div.py ........                                                   [ 40%]
tests/test_exp.py ........                                                   [ 51%]
tests/test_gelu.py ........                                                  [ 62%]
tests/test_mm.py ..                                                          [ 65%]
tests/test_mul.py ........                                                   [ 77%]
tests/test_relu.py ........                                                  [ 88%]
tests/test_rsqrt.py ........                                                 [100%]
                                                                                    
========================== 70 passed in 80.04s (0:01:20) ===========================

[voltjia]

Please use Markdown syntax to denote a word or phrase as code in the commit messages:

1. Add relu operator
2. Remove the asterisk in the declaration of function relu in src/ntops/torch.py
3. Add inplace parameter for relu

In src/ntops/kernels/relu.py, we don't actually need a replace parameter, because we can implement the inplace logic in src/ntops/torch.py:

def relu(input, inplace=False):
    if inplace:
        output = input
    else:
        output = torch.empty_like(input)

    kernel = ntops.kernels.relu.make(input.ndim)

    kernel(input, output)

    return output

Please change src/ntops/torch.py and tests/test_relu.py accordingly.

In addition, we use Ruff as our Python linter and code formatter. Please run the following before each commit:

ruff format
ruff check

[voltjia]

Nice work! There's just one last minor issue: In tests/test_relu.py, is replace a typo? If so, please change it to inplace.