fix fill hole lost expected backquote

[July541]

Fix #1690.
I match the backquote as the solution, but I am not sure that is an appropriate way to update the range at this function.

[OliverMadine]

Hello,

This has an issue when the hole needs to be filled with an infix operator since in this case, it should not have any backquotes. For example, the action "replace _ with (+)" will fill the hole with `(+)` rather than +.

[July541]

Hello,

This has an issue when the hole needs to be filled with an infix operator since in this case, it should not have any backquotes. For example, the action "replace _ with (+)" will fill the hole with (+) rather than +.

Thanks,
I made a silly mistake.