clarify vector extension documentation

[tariqkurd-repo]

Referring to: https://github.com/riscv/riscv-isa-manual/blob/main/src/vector-crypto.adoc

There are so many vector instructions included in so many different extensions it's really hard to determine which instructions are included where. As a case in point, vsha2ms.vv is included in 5 different extensions Zvkn, Zvknc, Zvkng, zvknh[ab]

It would make it easier to understand if the instruction summary tables such as:

all had an extra column giving the full list of extensions in which the instructions are included.

Trying to work out whether each instruction in included in the profiles makes this whole thing even harder to deal with (see riscv/riscv-profiles#201), summary tables in the ISA spec would really help make sense of what's going on.