Tracking issue for 0.10

[pacak]

• Hidden commands are not checked for validity/invariants #380
• Is there an API to output the shell completion file manually in the script? #379
• A way to prevent parsing of options after positionals #359
• Add support for env-only args for derive #344
• Format control over bpaf footer? #339
• Support deprecated options #331
• Generate help subcommand #323
• Weird formatiing of "multi value" options in usage #322
• impl<T> Parser<T> for Vec<Box<dyn Parser<T>>> #314
• currently any takes 3 type parameters, third one serves no purpose #306
• compile time failure for positional invariant violation #297
• Unified datatype for all the primitive parsers #294
• adjacent is not working if first argument requires more than one item to succeed #292
• --version and --help permit invalid arguments #288
• better Meta for Parseflag/ParseArgument with no names? #284
• Custom Help Section for group with exclusively hidden subcommands #277
• change bpaf into something that just reexports derive macro + core #276
• Make split_os_argument aware of short flag and argument names? #269
• Potential breaking changes for the next big release #239
• capitalization typo suggestions -h vs -H? #213
• Expose metadata for test assertions #407
• clarify special handling of blank lines in various help places
• custom text in version? extend fail with print_and_exit?
• print and exit primitive #409