docs: fix typo in docstring of Image.flip_horizontally (#589)

Closes #583

### Summary of Changes

Replace `Ìmage` with `Image` in docstring of `Image.flip_horizontally`.

src/safeds/data/image/containers/_image.py

@@ -345,7 +345,7 @@ def flip_vertically(self) -> Image:
 
     def flip_horizontally(self) -> Image:
         """
-        Return a new `Ìmage` that is flipped horizontally (vertical axis, flips left-right and vice versa).
+        Return a new `Image` that is flipped horizontally (vertical axis, flips left-right and vice versa).
 
         The original image is not modified.