add ability to check if value does not contain something

[fdncred]

Description

adds the ability to check if a value does not contain something.

check if contains
[one two three four] | str contains o

check if it does not contain
[one two three four] | str contains -n o

Tests

Make sure you've run and fixed any issues with these commands:

• cargo fmt --all -- --check to check standard code formatting (cargo fmt --all applies these changes)
• cargo clippy --all --all-features -- -D warnings -D clippy::unwrap_used -A clippy::needless_collect to check that you're using the standard code style
• cargo build; cargo test --all --all-features to check that all the tests pass