Bump third_party/tools/moore from `4f91804` to `4423b47`

[dependabot[bot]]

Bumps third_party/tools/moore from 4f91804 to 4423b47.

Commits

• 4423b47 Update README.md
• fd59d66 Replace llhd shifts with dynamic extracts and comb shifts (#247)
• cb0053b Surround moore.mir.concat with conversion casts to pass values of the type th...
• 064d55b readme: Update LLVM/CIRCT build instructions
• 6052a23 vhdl: Silence a few warnings for the time being
• 789dbac Bump CIRCT
• d0c5a3a readme: Fix missing "host" LLVM target
• 894ae30 codegen: Emit concat expr as moore.mir.concat op
• 0405d16 bin: Allow unregistered MLIR dialects to facilitate experimentation
• fb20be7 mlir: Impl PartialEq, Eq, Hash for MlirValue
• Additional commits viewable in compare view

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