feat(version-scanner): implement targeted namespaced ignore pragmas

[chalmerlowe]

This PR implements ignore pragmas to allow granular and self-expiring ignores to help fend off false positives in places where we need to leave references to specific strings:

# version-scanner: ignore-rule=rule_name:version

Example:

Imagine searching for "Python 3.7". We have a variety of rules to cover multiple circumstances. One rule matches solely on the version number (e.g. "3.7" in case the reference is an edge case not covered by other more specific and complicated rules).

Thus if we find "3.7" in a situation unrelated to Python, we will have a false positive such as this:
matplotlib==3.7.2

We can flag a line like this to be ignored under one of the numerous rules we have for categorizing matches (e.g explicit_version_string, dependency_requirement, combined_version_string, etc.) so that it does not trigger a false positive in the future. In this case we detected it under the explicit_version_string pattern so we flag it to be ignored under that rule, if the search is for 3.7.

matplotlib==3.7.2 # version-scanner: ignore-rule=explicit_version_string:3.7

You might ask: but what about when we need to find versions of matplotlib so we can update references to them?

If instead of Python, we were to search for "matplotlib 3.7.2" we would get a match. As a non-Python match, it would be caught under the dependency_requirement rule instead of the explicit_* rule.

[gemini-code-assist]

Code Review

This pull request adds support for targeted rule ignoring in the version scanner using the version-scanner: ignore-rule=<rule_name>:<version> pragma, along with corresponding unit tests. Feedback was provided to convert the version value to a string before calling re.escape to avoid potential runtime TypeError exceptions if a non-string version (such as a float or integer) is specified in the rule configuration.

[chalmerlowe]

This is marked "DO NOT MERGE" simply because it is blocked by a precursor PR. It is fine to review this PR and approve, but it should not be merged until that other PR is merged.

[hebaalazzeh]

LGTM! just one suggestion to cast the rule name and version to strings before escaping them. This will prevent potential TypeError exceptions if a version (like 3.7) is ever parsed from the config as a float instead of a string.