fixup neumann_series(): maxiter param

Co-authored-by: Maximilian-Stefan-Ernst <34346372+Maximilian-Stefan-Ernst@users.noreply.github.com>

Author: alyst

src/additional_functions/helper.jl

@@ -1,11 +1,11 @@
 # Neumann series representation of (I - mat)⁻¹
-function neumann_series(mat::SparseMatrixCSC; maxn::Integer = size(mat, 1))
+function neumann_series(mat::SparseMatrixCSC; maxiter::Integer = size(mat, 1))
     inverse = I + mat
     next_term = mat^2
 
     n = 1
     while nnz(next_term) != 0
-        (n <= maxn) || error("Neumann series did not converge in $maxn steps")
+        (n <= maxiter) || error("Neumann series did not converge in $maxiter steps")
         inverse += next_term
         next_term *= mat
         n += 1