Use top-level path in fileutils.rbs to suppress deprecation warning

[ksss]

Summary

• FileUtils::path is deprecated in favor of the top-level path type.
• Replace internal references in stdlib/fileutils/0/fileutils.rbs so steep check --validate=library no longer emits RBS::DeprecatedTypeName warnings.
• The deprecated alias (type path = ::path) and its %a{deprecated: ...} annotation are kept for backward compatibility.

../rbs/stdlib/fileutils/0/fileutils.rbs:192:18: [warning] Type `::FileUtils::path` is deprecated: Use top-level `path` instead
│ Diagnostic ID: RBS::DeprecatedTypeName
│
└   type pathlist = path | Array[path]
                    ~~~~

../rbs/stdlib/fileutils/0/fileutils.rbs:192:31: [warning] Type `::FileUtils::path` is deprecated: Use top-level `path` instead
│ Diagnostic ID: RBS::DeprecatedTypeName
│
└   type pathlist = path | Array[path]
                                 ~~~~

../rbs/stdlib/fileutils/0/fileutils.rbs:231:17: [warning] Type `::FileUtils::path` is deprecated: Use top-level `path` instead
│ Diagnostic ID: RBS::DeprecatedTypeName
│
└   def self?.cd: (path dir, ?verbose: boolish) -> void
                   ~~~~

...

Test plan

• bundle exec steep check --validate=library

Generated with Claude Code