AbsolutePath.IsPrefixOf is not segment-aware, unlike LocalPath.IsPrefixOf

[ForNeVeR]

AbsolutePath.IsPrefixOf and LocalPath.IsPrefixOf both <inheritdoc/> the same IPath{TPath}.IsPrefixOf contract, but they behave differently: the AbsolutePath one is a raw string prefix check, so a directory is reported as a prefix of a sibling whose name merely starts with the same characters.

Affects 1.12.0 (latest).

Reproduction

var dir = new AbsolutePath("/p/sub");
dir.IsPrefixOf(new AbsolutePath("/p/subx/a.txt"));                  // true  <-- unexpected
new LocalPath("/p/sub").IsPrefixOf(new LocalPath("/p/subx/a.txt")); // false <-- expected

// the two agree for a genuine child:
dir.IsPrefixOf(new AbsolutePath("/p/sub/a.txt"));                   // true

Cause

LocalPath.IsPrefixOf checks that the match ends on a separator boundary, and AbsolutePath.IsPrefixOf does not:

// AbsolutePath.cs
public bool IsPrefixOf(AbsolutePath other) =>
    Value.Length <= other.Value.Length && other.Value.StartsWith(Value);

// LocalPath.cs
public bool IsPrefixOf(LocalPath other)
{
    if (!(Value.Length <= other.Value.Length && other.Value.StartsWith(Value))) return false;
    return other.Value.Length == Value.Length || other.Value[Value.Length] == Separator;
}

Expected: AbsolutePath.IsPrefixOf applies the same separator-boundary check, so it agrees with LocalPath.IsPrefixOf on identical paths. (StartsWith is a plain string comparison in both types, which is consistent — only IsPrefixOf differs.)