Remove useless fragments

[axelboc]

I found an old stash from a past attempt at upgrading TypeScript from 5.0 to 5.2. Turns out I missed this refactoring opportunity when I looked at it again in #1636.

I had also taken some notes of interesting changes in 5.1 and 5.2 in case this is of interest:

Typescript 5.1

• Easier Implicit Returns for undefined-Returning Functions: a return statement is still required for all code paths, and it feels weird having return; at the end of a function; I much prefer the explicitness of return undefined;. Might help simplify other cases that I'm not seeing. 🤷‍♀️
• Decoupled Type-Checking Between JSX Elements and JSX Tag Types - at last, no more wrapping stuff in unnecessary fragments, like return <>{children}</>! 🎉
• Linked Cursors for JSX Tags 🎉
• Avoiding Unnecessary Type Instantiation - FYI, type checking performance improvements, notably for MUI

TypeScript 5.2

• Easier Method Usage for Unions of Arrays - we can finally loop through arrays of type ~number[] | TypedArray~ number[] | string[] with filter, map, etc. but now that I'm looking through the code, I can no longer recall a specific case where we had to work around this limitation... EDIT: we encountered this in getBounds with NumArray, a union of plain and typed arrays, which isn't covered here.
• Copying Array Methods - immutable arr.toReversed(), arr.toSorted(), etc. are now supported by TS ... but they still need to be polyfilled for older browsers, so not worth using yet.
• Comma Completions for Object Members - nice!
• Inline Variable Refactoring - cool also

[loichuder]

TypeScript 5.2

* [Easier Method Usage for Unions of Arrays](https://devblogs.microsoft.com/typescript/announcing-typescript-5-2/#easier-method-usage-for-unions-of-arrays) - we can finally loop through arrays of type `number[] | TypedArray` with
  `filter`, `map`, etc. but now that I'm looking through the code, I can no longer recall a specific case where we had to work around this limitation... 🤷‍♀️

IIRC, it was for the bounds computation: https://github.com/silx-kit/h5web/blob/86848a7fe2fd9e11563276c3ddc41eae764711e6/packages/shared/src/vis-utils.ts#L128

[axelboc]

IIRC, it was for the bounds computation:

Ooh nice! :fishing_pole_and_fish:

[axelboc]

Arf no luck, seems to work only with unions of plain arrays, like number[] | string[], not with unions of typed and plain arrays like in the case of the NumArray type in getBounds. :cry: