feat(csr): inherit attrs from aliases

[blazethunderstorm]

Closes #781

Made CSR field aliases automatically inherit missing attributes like description, type, and reset value from the original field. This avoids duplication and keeps alias definitions cleaner and less error-prone.

[ThinkOpenly]

Thanks for the efforts here.

The desired solution for #781 is more general, though. It's very likely that the realization will be something like $inherits usage, and this may be worth a try as an explicit solution (rather than something magical in the Ruby code). See examples of usage in the instruction YAML files in spec/std/isa/inst/B. If you can replace the duplicated attributes in the CSR aliases with $inherits and verify it's doing what's expected by generating a "resolved spec" (./do gen:resolved_arch) and looking at the aliased fields, then you're in good shape.

If this doesn't make sense, do ask questions. A learning curve is certainly normal and expected. :-)