DOC: Fix parameter names in private helper docstrings

Ten docstrings name a parameter that is not in the signature, so
help() and editor tooltips show an argument that raises TypeError.

Renames, one to one:
- _lin_field_coeff and _do_lin_field_coeff: rmag/cosmag -> rmags/cosmags.
  The line just below already says 'for each rmag/cosmag/w', so the
  singular there is the element, the parameter is the plural.
- write_named_matrix: matkind -> mat. mat was undocumented.
- text2d: x/y -> x_window/y_window.
- _cart_to_sph: cart_pts -> cart.
- _sss_basis: coils -> all_coils.

And one wrong default: _ajd_pham documents max_iter=1000, the signature
has 15. pyRiemann, which the comment credits as the source, uses 20.

Docstrings only.

Author: karpovantonme

doc/changes/dev/14134.other.rst

@@ -0,0 +1 @@
+Fix ten docstrings in private helpers that named a parameter the function does not take, and one that documented ``max_iter=1000`` for :func:`mne.decoding.csp._ajd_pham` while the signature has ``15``, by `Anton Karpov`_.

mne/_fiff/matrix.py

@@ -103,7 +103,7 @@ def write_named_matrix(fid, kind, mat):
         The opened file descriptor.
     kind : int
         The kind of the matrix.
-    matkind : int
+    mat : int
         The type of matrix.
     """
     # let's save ourselves from disaster

mne/decoding/csp.py

@@ -613,7 +613,7 @@ def _ajd_pham(X, eps=1e-6, max_iter=15):
         A set of covariance matrices to diagonalize.
     eps : float, default 1e-6
         The tolerance for stopping criterion.
-    max_iter : int, default 1000
+    max_iter : int, default 15
         The maximum number of iteration to reach convergence.
 
     Returns

mne/forward/_compute_forward.py

@@ -68,9 +68,9 @@ def _lin_field_coeff(surf, mult, rmags, cosmags, ws, bins, n_jobs):
     mult : float
         Multiplier for particular BEM surface (Iso Skull Approach discussed in
         Mosher et al., 1999 and Hämäläinen and Sarvas, 1989 Section III?)
-    rmag : ndarray, shape (n_integration_pts, 3)
+    rmags : ndarray, shape (n_integration_pts, 3)
         3D positions of MEG coil integration points (from coil['rmag'])
-    cosmag : ndarray, shape (n_integration_pts, 3)
+    cosmags : ndarray, shape (n_integration_pts, 3)
         Direction of the MEG coil integration points (from coil['cosmag'])
     ws : ndarray, shape (n_integration_pts,)
         Weights for MEG coil integration points
@@ -116,9 +116,9 @@ def _do_lin_field_coeff(bem_rr, tris, tn, ta, rmags, cosmags, ws, bins):
         Triangle unit normal vectors
     ta : ndarray, shape (n_BEM_vertices,)
         Triangle areas
-    rmag : ndarray, shape (n_sensor_pts, 3)
+    rmags : ndarray, shape (n_sensor_pts, 3)
         3D positions of MEG coil integration points (from coil['rmag'])
-    cosmag : ndarray, shape (n_sensor_pts, 3)
+    cosmags : ndarray, shape (n_sensor_pts, 3)
         Direction of the MEG coil integration points (from coil['cosmag'])
     ws : ndarray, shape (n_sensor_pts,)
         Weights for MEG coil integration points

mne/preprocessing/maxwell.py

@@ -1702,7 +1702,7 @@ def _sss_basis(exp, all_coils):
             ext_order : int
                 Order of the external multipolar moment space
 
-    coils : list
+    all_coils : list
         List of MEG coils. Each should contain coil information dict specifying
         position, normals, weights, number of integration points and channel
         type. All coil geometry must be in the same coordinate frame

mne/transforms.py

@@ -773,7 +773,7 @@ def _cart_to_sph(cart):
 
     Parameters
     ----------
-    cart_pts : ndarray, shape (n_points, 3)
+    cart : ndarray, shape (n_points, 3)
         Array containing points in Cartesian coordinates (x, y, z)
 
     Returns

mne/viz/backends/_abstract.py

@@ -555,10 +555,10 @@ def text2d(
 
         Parameters
         ----------
-        x : float
+        x_window : float
             The X component to use as position of the text in the
             window coordinates system (window_width, window_height).
-        y : float
+        y_window : float
             The Y component to use as position of the text in the
             window coordinates system (window_width, window_height).
         text : str