Remove the prop_remove just before prop_add in place_virtual_text, since this function is called after clear_virtual_text is called to clear the previously added virtual text.
That way, if there are multiple virtual text to place on the same line with the same severity, the following ones don't replace the former ones. Besides, the branch for neovim wasn't removing any property, so this should make it consistent with neovim.
Remove the prop_remove just before prop_add in place_virtual_text, since this function is called after clear_virtual_text is called to clear the previously added virtual text.
That way, if there are multiple virtual text to place on the same line with the same severity, the following ones don't replace the former ones. Besides, the branch for neovim wasn't removing any property, so this should make it consistent with neovim.