Fix contraction of '--' to '-' in Info format of Line Styles (bug #41585) * plot.txi: Can't use @qcode macro for '--' because it doesn't create a verbatim environment like @code. In this case, '--' is replaced by single en-dash in Info format. Instead, use explicit @ifinfo and @verb blocks to create '--' in Info format. * DASPK-opts.in: Add missing escaped quote (\") to documentation. * validateattributes.m: Remove extra ',' typo and end of @qcode instantiation.