Replace force unwrapping with XCTUnwrap for safer tests

Use XCTUnwrap() instead of force unwrapping to handle potential nil
values more gracefully and prevent test traps, as suggested in PR review.

Author: agisilaos

Tests/SwiftDocCTests/Infrastructure/DocumentationContext/DocumentationContext+RootPageTests.swift

@@ -212,7 +212,7 @@ class DocumentationContext_RootPageTests: XCTestCase {
         // Verify each warning has a solution to remove the TechnologyRoot directive
         for problem in multipleRootsProblems {
             XCTAssertEqual(problem.possibleSolutions.count, 1)
-            let solution = problem.possibleSolutions.first!
+            let solution = try XCTUnwrap(problem.possibleSolutions.first)
             XCTAssertEqual(solution.summary, "Remove the 'TechnologyRoot' directive")
             XCTAssertEqual(solution.replacements.count, 1)
         }