[clang] [llvm] [mlir] [clang][APFloat] Print floating-point literals in the shortest round-trip form (PR #218471)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman approved this pull request.

LGTM, but let's give the other reviewers a chance to sign off as well before landing.

https://github.com/llvm/llvm-project/pull/218471