Improve changelog entry

Author: ValerianRey

CHANGELOG.md

@@ -10,12 +10,13 @@ changelog does not include internal changes that do not affect the user.
 
 ### Changed
 
-- **BREAKING**: Removed the concepts of generalized Gramian, `PSDTensor`, `GeneralizedWeighting`,
-  and `Flattening`. The `Engine.compute_gramian` method now always returns a square matrix of shape
-  `[m, m]`, where `m` is the total number of elements of the ``output`` tensor (treating all
-  dimensions uniformly). Previously, an output of shape `[m_1, m_2]` would return a 4D generalized
-  Gramian of shape `[m_1, m_2, m_2, m_1]`; it now returns a `[m_1 * m_2, m_1 * m_2]` matrix. To
-  update, replace `Flattening(weighting)` with a standard `Weighting` and reshape the resulting
+- **BREAKING**: Remove entirely the concept of generalized Gramians. The `Engine.compute_gramian`
+  method now always returns a square matrix of shape `[m, m]`, where `m` is the total number of
+  elements of the ``output`` tensor (treating all dimensions uniformly). Previously, an output of
+  shape `[m_1, m_2]` would return a 4D generalized Gramian of shape `[m_1, m_2, m_2, m_1]`; it now
+  returns a `[m_1 * m_2, m_1 * m_2]` matrix.
+  This also removes `GeneralizedWeighting` and `Flattening`.
+  To update, replace `Flattening(weighting)` with a standard `Weighting` and reshape the resulting
   weight vector yourself:
   ```python
   # Before