I wonder if this could be too specific? Maybe there are cases where it is legitimite to treat the 'n' in '\n' as whole word if the context does not know about escape sequences.
The behavior can be changed by adding '\' to the `wordchars` settings in `filetypes.common` and the filetype definition files for the various filetypes. For details, see https://geany.org/manual/#filetype-configuration.