Update isingxy latex definition (PennyLaneAI#2858)

* update isingxy latex definition

* update the changelog

* move to bug fixes

* Update doc/releases/changelog-dev.md

Co-authored-by: Lee James O'Riordan <mlxd@users.noreply.github.com>

* Update changelog-dev.md

Co-authored-by: Lee James O'Riordan <mlxd@users.noreply.github.com>
Co-authored-by: Romain Moyard <rmoyard@gmail.com>

doc/releases/changelog-dev.md

@@ -388,6 +388,9 @@ of operators. [(#2622)](https://github.com/PennyLaneAI/pennylane/pull/2622)
 
 <h3>Bug fixes</h3>
 
+* Updated IsingXY gate doc-string.
+  [(#2858)](https://github.com/PennyLaneAI/pennylane/pull/2858)
+
 * Fixes a bug where the parameter-shift gradient breaks when using both
   custom `grad_recipe`s that contain unshifted terms and recipes that
   do not contains any unshifted terms.
@@ -428,5 +431,5 @@ This release contains contributions from (in alphabetical order):
 
 Samuel Banning, Juan Miguel Arrazola, Utkarsh Azad, David Ittah, Soran Jahangiri, Edward Jiang,
 Ankit Khandelwal, Christina Lee, Sergio Martínez-Losa, Albert Mitjans Coma, Ixchel Meza Chavez,
-Romain Moyard, Lee James O'Riordan, Mudit Pandey, Bogdan Reznychenko, Jay Soni, Antal Száva,
+Romain Moyard, Lee James O'Riordan, Mudit Pandey, Bogdan Reznychenko, Shuli Shu, Jay Soni, Antal Száva,
 David Wierichs, Moritz Willmann

pennylane/ops/qubit/parametric_ops.py

@@ -2767,7 +2767,7 @@ class IsingXY(Operation):
     r"""
     Ising (XX + YY) coupling gate
 
-    .. math:: \mathtt{XY}(\phi) = \exp(-i \frac{\theta}{4} (X \otimes X + Y \otimes Y)) =
+    .. math:: \mathtt{XY}(\phi) = \exp(i \frac{\theta}{4} (X \otimes X + Y \otimes Y)) =
         \begin{bmatrix}
             1 & 0 & 0 & 0 \\
             0 & \cos(\phi / 2) & i \sin(\phi / 2) & 0 \\