Double spaces have fallen out of favor in recent years because they no longer contribute to readability.
We have been using single spaces and editing related paragraphs for some time, but now it seems best to update the remaining instances to avoid churn in unrelated commits and to make it clearer what spacing contributors should use.
This allows options to be marked as beta, which will require that the --beta option be supplied to prevent accidental usage of a beta feature.
The online and command-line documentation also show warnings when options are beta.
The prior range checking was done based on the valid values for gz. While this worked it was a subset of what is available for lz4 and zst.
Allow the range to be specified for each compress-type. Adding this functionality to the parse module would be a better solution but that is a bigger project than this fix deserves, at least for now.
Command-line help is now generated at build time so it does not need to be committed. This reduces churn on commits that add configuration and/or update the help.
Since churn is no longer an issue, help.auto.c is bzip2 compressed to save space in the binary.
The Perl config parser (Data.pm) has been moved to doc/lib since the Perl build path is no longer required.
Likewise doc/xml/reference.xml has been moved to src/build/help/help.xml since it is required at build time.
