Fix T97927: bpy.utils.units.to_string uses wrong units for velocity, acceleration, lens length, and power

`TEMPERATURE` type was also missing, not only the new-ish
`TIME_ABSOLUTE` one...

Added a static assert on the size of the `bpyunits_ucategories_items`
array, and a comment on anonymous enum of `B_UNIT_`, in the hope this
won't happen again in the future.

source/blender/python/intern/bpy_utils_units.c

@@ -43,13 +43,19 @@ static const char *bpyunits_ucategories_items[] = {
     "MASS",
     "ROTATION",
     "TIME",
+    "TIME_ABSOLUTE",
     "VELOCITY",
     "ACCELERATION",
     "CAMERA",
     "POWER",
+    "TEMPERATURE",
     NULL,
 };
 
+BLI_STATIC_ASSERT(
+    ARRAY_SIZE(bpyunits_ucategories_items) == B_UNIT_TYPE_TOT + 1,
+    "`bpyunits_ucategories_items` should match `B_UNIT_` enum items in `BKE_units.h`")
+
 /**
  * These fields are just empty placeholders, actual values get set in initializations functions.
  * This allows us to avoid many handwriting, and above all,