Update diagrams and minor fix to text

[geoffthorpe-mips]

• the diagrams now show transactions from all privilege levels
• improved visual consistency
• correction that Smlwidlist depends on Smlwid, not Smwid. (Though if Smwid is not enabled, then mlwidlist can't be lockable.)

[pperesse]

Similar issues are there in the RISC-V ISA World-ID Extensions section at the beginning, where we provide an overview and list of all the extensions.

The Smlwidlist extension depends on the Smwid extension

and

The only extension that is dependent on Smwid is Smlwidlist, the other Worlds extensions have no dependence on Smwid. If the Smwid extension is not enabled, the mwid CSR does not exist. If Smwid is enabled, the platform determines whether mwid is locked or unlocked on-reset.

Also, since you have a PR open, can we mention in this section the pinstraps associated with each extension? This is a feedback that was made to me directly which I think will provide clarity.

For instance:
With the Smwid extension, the mwid CSR is introduced to provide a lockable control of the WID value assigned to the hart and a platform-defined value pmwidlist may limit the set of WIDs that can be used with mwid.

The Smlwid extension introduces the mlwid CSR to control the WID of lower-privilege modes and a platform-defined value pmlwidlist may limit the set of WIDs that can be used with mlwid.

[geoffthorpe-mips]

I've (force-)pushed an update. Smlwidlist is declared as dependent on both Smwid and Smlwid, and I've added the requested clarifications on the platform values.

[pperesse]

Thanks @geoffthorpe-mips . Looks good to me