Add support for pathlib.Path to normalizeFilePath. (#784)

* Add support for pathlib.Path to `normalizeFilePath`.

Add `pathlib.Path` to exception documentation in `normalizeFilePath`.

* Update normalizers.py

- broadened scope of `Path.resolve` for improved robustness 
- document implicit exception.
- improved error message.
- corrected typo in docstring.

---------

Co-authored-by: knutnergaard <knutnergaard@users.noreply.github.com>

Lib/fontParts/base/normalizers.py

@@ -4,6 +4,7 @@
 from typing import TYPE_CHECKING, Any, Optional, Tuple, Type, Union
 from collections import Counter
 from fontTools.misc.fixedTools import otRound
+from pathlib import Path
 
 from fontParts.base.annotations import (
     T,
@@ -1138,17 +1139,22 @@ def normalizeGlyphNote(value: str) -> str:
 # File Path
 
 
-def normalizeFilePath(value: str) -> str:
+def normalizeFilePath(value: Union[str, Path]) -> str:
     """Normalize a file path.
 
-    :param value: The file path to normalize as a :class:`str`.
-    :return: A :class:`str` representing the noramlized file path.
-    :raises TypeError if `value` is not a :class:`str`.
+    Relative paths are resolved automatically.
+
+    :param value: The file path to normalize as a :class:`str` or :class:`pathlib.Path`.
+    :return: A :class:`str` representing the normalized file path.
+    :raises TypeError if `value` is not a :class:`str` or :class:`pathlib.Path`.
+    :raises FileNotFoundError: If the file path cannot be resolved because it does not exist.
 
     """
-    if not isinstance(value, str):
-        raise TypeError(f"File paths must be strings, not {type(value).__name__}.")
-    return value
+    if not isinstance(value, (str, Path)):
+        raise TypeError(
+            f"File paths must be strings or Path objects, not {type(value).__name__}."
+        )
+    return str(Path(value).resolve())
 
 
 # Interpolation