[ntuple] Change signature of RRealField::SetQuantized and deprecate old one

[silverweed]

Instead of

   SetQuantized(T min, T max, size_t nBits)

use

   SetQuantized(size_t nBits, pair<T, T> valueRange)

Rationale:

• keep nBits in first position to be more consistent with SetTruncated
• prevent mistakes of argument wrong ordering where nBits is passed first instead of min.

[github-actions]

Test Results

    22 files      22 suites   3d 12h 14m 36s ⏱️
 3 848 tests  3 848 ✅ 0 💤 0 ❌
76 908 runs  76 908 ✅ 0 💤 0 ❌

Results for commit fd935a3.

[jblomer]

Needs backporting to 6.40 if to be deprecated in 6.42.

[hahnjo]

If we deprecate in 6.40 and remove "already" in 6.42 (which needs synchronization with #22023), users will have little time to migrate. Maybe that's fine because 6.40 will be an LTS and probably few users call SetQuantized, apart from the RNTuple validation suite...

[silverweed]

@hahnjo I'm pretty sure the quantized floats are advanced enough to be currently almost unused and the change is purely mechanical, so I think we can afford it. But I'm also fine deprecating it in 6.40 and removing it in 6.44.

[hahnjo]

Fair enough. Still need to pay attention after #22023 is now merged, in master it must be immediately removed.

[silverweed]

/backport to 6.40

[root-project-bot]

Preparing to backport PR #22084 to branch 6.40 requested by silverweed

[root-project-bot]

This PR has been backported to branch 6.40: #22107