maths/number_of_digits.py: Streamline benchmarks (#7913)
maths/number_of_digits.py: Streamline benchmarks (#7913)

* maths/number_of_digits.py: Streamline benchmarks

```
num_digits(262144): 6 -- 0.2226011250168085 seconds
num_digits_fast(262144): 6 -- 0.13145116699161008 seconds
num_digits_faster(262144): 6 -- 0.09273383300751448 seconds

num_digits(1125899906842624): 16 -- 0.6056742920191027 seconds
num_digits_fast(1125899906842624): 16 -- 0.15698366600554436 seconds
num_digits_faster(1125899906842624): 16 -- 0.1027024170034565 seconds

num_digits(1267650600228229401496703205376): 31 -- 1.1957934170495719 seconds
num_digits_fast(1267650600228229401496703205376): 31 -- 0.15552304196171463 seconds
num_digits_faster(1267650600228229401496703205376): 31 -- 0.13062308297958225 seconds
```

* updating DIRECTORY.md

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update number_of_digits.py

Co-authored-by: github-actions <47a35b99ddbe74edbea9dad62cf9a3b212194173@users.noreply.github.com>
Co-authored-by: pre-commit-ci[bot] <3ea08453efb076ca910552532a53973a6527df40@users.noreply.github.com>
TheAlgorithms/Python