`log-parser` exercise refers to removed modules from stdlib

[winstoncheong]

This is related to issue #542.
The log-parser exercise was missed in its resolution.

The following still refer to the previous gleam/regex module instead of gleam/regexp and https://hexdocs.pm/gleam_regexp/gleam/regexp.html:

• https://github.com/exercism/gleam/blob/main/exercises/concept/log-parser/.docs/hints.md
• https://github.com/exercism/gleam/blob/main/exercises/concept/log-parser/.docs/introduction.md

[lpil]

Thank you