feat: correct pluralization of localized units

This commits involves a heavy refactoring of the helper function for
the formatter. Briefly, before the same function that was generating
the string was splitting beween numerator and denominator. Now this
is done before to allow for correct pluralization.

pint/compat.py

@@ -16,20 +16,11 @@
 from decimal import Decimal
 from importlib import import_module
 from numbers import Number
-from typing import Any, NoReturn
-
-try:
-    from uncertainties import UFloat, ufloat
-    from uncertainties import unumpy as unp
-
-    HAS_UNCERTAINTIES = True
-except ImportError:
-    UFloat = ufloat = unp = None
-    HAS_UNCERTAINTIES = False
-
-
-from typing import TypeAlias  # noqa
-
+from typing import (
+    Any,
+    NoReturn,
+    TypeAlias,  # noqa
+)
 
 if sys.version_info >= (3, 11):
     from typing import Self  # noqa
@@ -78,6 +69,17 @@ class BehaviorChangeWarning(UserWarning):
     pass
 
 
+try:
+    from uncertainties import UFloat, ufloat
+    from uncertainties import unumpy as unp
+
+    HAS_UNCERTAINTIES = True
+except ImportError:
+    UFloat = ufloat = unp = None
+
+    HAS_UNCERTAINTIES = False
+
+
 try:
     import numpy as np
     from numpy import datetime64 as np_datetime64
@@ -172,6 +174,9 @@ def _to_magnitude(value, force_ndarray=False, force_ndarray_like=False):
 except ImportError:
     HAS_BABEL = False
 
+    babel_parse = missing_dependency("Babel")  # noqa: F811 # type:ignore
+    babel_units = babel_parse
+
 try:
     import mip
 
@@ -186,6 +191,14 @@ def _to_magnitude(value, force_ndarray=False, force_ndarray_like=False):
 except ImportError:
     HAS_MIP = False
 
+    mip_missing = missing_dependency("mip")
+    mip_model = mip_missing
+    mip_Model = mip_missing
+    mip_INF = mip_missing
+    mip_INTEGER = mip_missing
+    mip_xsum = mip_missing
+    mip_OptimizationStatus = mip_missing
+
 # Defines Logarithm and Exponential for Logarithmic Converter
 if HAS_NUMPY:
     from numpy import (
@@ -198,18 +211,6 @@ def _to_magnitude(value, force_ndarray=False, force_ndarray_like=False):
         log,  # noqa: F401
     )
 
-if not HAS_BABEL:
-    babel_parse = missing_dependency("Babel")  # noqa: F811
-    babel_units = babel_parse
-
-if not HAS_MIP:
-    mip_missing = missing_dependency("mip")
-    mip_model = mip_missing
-    mip_Model = mip_missing
-    mip_INF = mip_missing
-    mip_INTEGER = mip_missing
-    mip_xsum = mip_missing
-    mip_OptimizationStatus = mip_missing
 
 # Define location of pint.Quantity in NEP-13 type cast hierarchy by defining upcast
 # types using guarded imports