Shared: Overhaul the AlertFiltering QLDoc

[cklin]

This PR strengthens the contract for the restrictAlertsTo and the restrictAlertsToExactLocation extensible predicates.

• restrictAlertsTo is now documented to match any alert location that intersects with a specified line range. (Previously an alert location matches only when its first line is in a specified line range.)
• restrictAlertsToExactLocation is now documented to match any alert location that wholly contains a specific character range. (Previously an alert location matchis only when it is exactly the same as a specified character range.)

It also contains misc wording changes for clarity.

[cklin]

@jbj @hvitved

This is a documentation update follow-up to #19943, concerning support for approximate locations. (That PR changes restrictAlertsTo diff-range location matching from "match the first line of location only" to "test whether the location intersects with the diffrange".)

#19943 treats support for approximate locations as an implementation detail that is not documented (nor expected to be documented.) This PR treats the same support for approximate locations as the new specification for restrictAlertsTo (and restrictAlertsToExactLocation), so that all other users of diff-informed queries, on both the QL authoring side and the CI integration side, can take advantage of this more general (and, I believe, more useful) behavior.

[jbj]

LGTM! It's great to see the documentation shrinking and becoming clearer while the use cases for diff-informed queries expand just by changing the spec to match the implementation.

Cc @asgerf.

[Copilot]

Pull Request Overview

This PR updates the documentation for the AlertFiltering module to clarify and strengthen the contract for the restrictAlertsTo and restrictAlertsToExactLocation extensible predicates. The changes modify how alert location matching is defined - restrictAlertsTo now matches locations that intersect with a line range rather than just checking the first line, and restrictAlertsToExactLocation now matches locations that wholly contain a character range rather than requiring exact matches.

• Updated parameter names and documentation for restrictAlertsTo to clarify line range intersection behavior
• Modified restrictAlertsToExactLocation documentation to specify character range containment semantics
• Simplified and clarified various docstring explanations throughout the module