fix style errors in fs.relative_to implementation

In commit f52bcaa27f a few issues were
added:
- doc typo
- imports for utils.universal are not intended to be directly used, it's
  an internal wrapper that exists solely to make mesonlib work well as
  it always did while simultaneously allowing `meson --internal`
  codepaths to avoid importing anything other than an extremely stripped
  down core
- type annotation specific import was imported at runtime scope

docs/markdown/Fs-module.md

@@ -228,7 +228,7 @@ fs.stem('foo/bar/baz.dll.a')  # baz.dll
 
 *Since 1.3.0*
 
-Return a relative filepath. In event a relative path could not be found, the
+Return a relative filepath. In the event a relative path could not be found, the
 absolute path of `to` is returned. Relative path arguments will be assumed to be
 relative to `meson.current_source_dir()`.
 

mesonbuild/modules/fs.py

@@ -23,19 +23,13 @@ from .. import mlog
 from ..build import BuildTarget, CustomTarget, CustomTargetIndex, InvalidArguments
 from ..interpreter.type_checking import INSTALL_KW, INSTALL_MODE_KW, INSTALL_TAG_KW, NoneType
 from ..interpreterbase import FeatureNew, KwargInfo, typed_kwargs, typed_pos_args, noKwargs
-from ..interpreterbase.baseobjects import TYPE_kwargs
-from ..mesonlib import (
-    File,
-    MesonException,
-    has_path_sep,
-    path_is_in_root,
-)
-from ..utils.universal import relpath
+from ..mesonlib import File, MesonException, has_path_sep, path_is_in_root, relpath
 
 if T.TYPE_CHECKING:
     from . import ModuleState
     from ..build import BuildTargetTypes
     from ..interpreter import Interpreter
+    from ..interpreterbase import TYPE_kwargs
     from ..mesonlib import FileOrString, FileMode
 
     from typing_extensions import TypedDict