Update inverse.rst DOC (mne-tools#10922)

* Update inverse.rst

Adds a note in the whitening section of Algorithms and other implementation details doc to clarify the forward model gain matrix is also average referenced during whitening.

* Update latest.inc

* Update names.inc

Author: mh105

doc/_includes/inverse.rst

@@ -150,6 +150,9 @@ to raw data. To reflect the decrease of noise due to averaging, this matrix,
 :math:`C_0`, is scaled by the number of averages, :math:`L`, *i.e.*, :math:`C =
 C_0 / L`.
 
+.. note::
+   When EEG data are included, the gain matrix :math:`G` needs to be average referenced when computing the linear inverse operator :math:`M`. This is incorporated during creating the spatial whitening operator :math:`C^{-^1/_2}`, which includes any projectors on the data. EEG data average reference (using a projector) is mandatory for source modeling and is checked when calculating the inverse operator. 
+
 As shown above, regularization of the inverse solution is equivalent to a
 change in the variance of the current amplitudes in the Bayesian *a priori*
 distribution.

doc/changes/latest.inc

@@ -23,6 +23,8 @@ Current (1.1.dev0)
 
 Enhancements
 ~~~~~~~~~~~~
+- Add a note to clarify the inclusion of average referencing gain matrix during whitening (:gh:`10922` by :newcontrib:`Mingjian He`)
+
 - Add time axis scale bar for :meth:`mne.Epochs.plot` using matplotlib backend (:gh:`10736` by :newcontrib:`Jordan Drew`)
 
 - Add :func:`mne.bem.distance_to_bem` to find depth of source positions (:gh:`10632` by :newcontrib:`Matt Courtemanche`)

doc/changes/names.inc

@@ -457,3 +457,5 @@
 .. _Lukas Gemein: https://github.com/gemeinl
 
 .. _Frederik Weber: https://github.com/Frederik-D-Weber
+
+.. _Mingjian He: https://github.com/mh105