`check_spelling()` unable to handle dubble trailing backslash \\

[wlangera]

I get an error for the check_spelling() function when trailing backslashes are in my text or in my mathematical formulas.
Some examples of text that generate the errors:

This is a sentence \\

Creates the following error:

Error in gregexpr(spelling_clean_problem(word), text[i]) : 
  invalid regular expression '\\\', reason 'Trailing backslash

--
This is a sentence\\

Creates the following error:

Error in gregexpr(spelling_clean_problem(word), text[i]) : 
invalid regular expression 'sentence\\\', reason 'Trailing backslash'

--
\\ This is a sentence

Creates the following error:

Error in gregexpr(spelling_clean_problem(word), text[i]) : 
  invalid regular expression '\\\', reason 'Trailing backslash

--

$$
p(\mathbf{z_i}) = \begin{cases}
      \int_0^W\frac{2r}{W^2}g(r, \mathbf{z_i};\boldsymbol \theta)\,dr, & \text{punttransecten} \\
      \int_0^W\frac{1}{W}g(r, \mathbf{z_i};\boldsymbol \theta)\,dr, & \text{lijntransecten}
    \end{cases}
$$

Creates the following error:

Error in gregexpr(spelling_clean_problem(word), text[i]) : 
  invalid regular expression '\\\', reason 'Trailing backslash

Kind regards,
Ward