SLOI, SROI also need *_RV32 version; how REV, REV8, ORC_B instructions are related to b-ext.

1. Like RORI has RORI_RV32 version, I think SLOI and SROI also need *_RV32 version.
https://github.com/chipsalliance/rocket-chip/blob/f1521796c292ee87958df6ea52f12145d869c83f/src/main/scala/rocket/Instructions.scala#L823

2. REV, REV8, ORC_B are instructions from Zbb, while bitmanip defines them as pseudo instructions. Is it hte case? where is the REV, REV8 and ORC_B spec definitions?

Start with the referenced Instructions.scala entry around line 823 and compare the existing RORI_RV32 definition with SLOI and SROI. Then verify the RISC-V bitmanip specification for REV, REV8, and ORC_B and determine whether Rocket Chip treats them as Zbb instructions or pseudo-instructions. Done means the RV32 variants and instruction relationships are correctly represented and verified against the specification.

Written by the indexing model from the issue text.