PathString.StartsWithSegments: Clarify trailing slash behavior in doc comments

[david-acker]

PathString.StartsWithSegments: Clarify trailing slash behavior in doc comments

Description

Adds remarks clarifying some unexpected behavior of trailing slashes with the StartsWithSegments methods on PathString.

Remarks

/// <remarks>
/// When the <paramref name="other"/> parameter contains a trailing slash, the <see cref="PathString"/> being checked
/// must either exactly match or include a trailing slash. For instance, for a <see cref="PathString"/> of "/a/b",
/// this method will return <c>true</c> for "/a", but will return <c>false</c> for "/a/".
/// Whereas, a <see cref="PathString"/> of "/a//b/" will return <c>true</c> when compared with "/a/".
/// </remarks>

Fixes #2713

[captainsafia]

@david-acker Doc change looks good! Thanks a ton for digging out this old gem from the backlog and taking a look at it. 😄

Could I trouble you to add a new test case here to document this behavior in test too? I did a look through and haven't seen existing coverage. Regardless, it might be good to have a test method of its own so it's easy to spot.

[david-acker]

@captainsafia Will do! Do you think this warrants four separate test methods for each of the StartsWithSegments overloads? I've added separate tests methods for each of these, but I can pare these down if you'd like.

[captainsafia]

LGTM! I'm OK with the tests for each overload. More tests is always better than less.