Dimension: add dunder methods (#10)

* dim dunders

* remove pos neg

* remove rpow

Author: andrewgsavage

src/metrology_apis/__init__.py

@@ -14,6 +14,12 @@ def __mul__(self, other: Self, /) -> Self: ...
     def __truediv__(self, other: Self, /) -> Self: ...
     def __pow__(self, other: int, /) -> Self: ...
 
+    def __rmul__(self, other: Self, /) -> Self: ...
+    def __rtruediv__(self, other: Self, /) -> Self: ...
+
+    def __eq__(self, other: Self, /) -> bool: ...
+    def __ne__(self, other: Self, /) -> bool: ...
+
 
 @runtime_checkable
 class Unit(Protocol):