Add global generic constraint support to type relationship helpers

[meziantou]

Motivation

MA0046 (Use EventHandler to declare events) recently added support for generic type parameter constraints, but this capability was isolated to a single analyzer. Other relationship-checking helpers like IsOrInheritFrom, Implements, and InheritsFrom lack this awareness, causing them to miss or incorrectly handle cases where a type parameter is constrained to a base type or interface. This creates inconsistency across the codebase and false positives/negatives in analyzers that rely on these helpers.

Approach

Centralized generic constraint resolution: Updated all type relationship helpers in TypeSymbolExtensions to recursively resolve generic type parameter constraints:

• InheritsFrom – now checks if constraint types inherit from the target
• Implements – now checks if constraint types implement the target interface
• ImplementsGenericInterface – now checks generic interface constraints
• IsOrImplements – simplified by delegating to Implements
• IsOrInheritFrom – combined type equality check with constraint resolution

Cycle-safe recursion: Added AnyConstraintTypeMatches helper that tracks visited type parameters using a HashSet to prevent infinite loops in recursive constraint chains.

Refactored consumers: Simplified UseEventHandlerOfTAnalyzer (MA0046) to use IsOrInheritFrom directly instead of maintaining its own constraint-traversal logic.

Changes

• TypeSymbolExtensions.cs: Added generic constraint awareness to five core helpers; introduced cycle-safe traversal
• UseEventHandlerOfTAnalyzer.cs: Removed local constraint recursion (14 lines → 2 lines)
• EventsShouldHaveProperArgumentsAnalyzerTests.cs: Added regression test for constrained generic delegate arguments
• docs/Rules/MA0046.md and docs/Rules/MA0093.md: Updated to note generic constraint support

Testing

• All 3289 existing tests pass
• Targeted tests pass on Roslyn 4.2 (earliest supported version)
• New test validates that EventsShouldHaveProperArgumentsAnalyzer correctly flags null EventArgs on constrained generic delegates
• Full test suite passes after documentation regeneration