Update black requirement from ~=25.11 to ~=26.5 in /client

[dependabot]

Updates the requirements on black to permit the latest version.

Release notes

Sourced from black's releases.

26.5.1

Stable style

• Fix unstable formatting of annotated assignments whose subscript annotation contains an inline comment (e.g. x: list[ # pyright: ignore[...]) (#5130)
• Preserve inline comments (including # type: ignore) immediately before a # fmt: skip line, avoiding AST equivalence failures (#5139)

Packaging

• Correct the version in the published executables (#5137)

Documentation

• Add Neovim integration guide covering conform.nvim, ALE, and simple command approaches (#5124)

Changelog

Sourced from black's changelog.

Version 26.5.1

Stable style

• Fix unstable formatting of annotated assignments whose subscript annotation contains an inline comment (e.g. x: list[ # pyright: ignore[...]) (#5130)
• Preserve inline comments (including # type: ignore) immediately before a # fmt: skip line, avoiding AST equivalence failures (#5139)

Packaging

• Correct the version in the published executables (#5137)

Documentation

• Add Neovim integration guide covering conform.nvim, ALE, and simple command approaches (#5124)

Version 26.5.0

Highlights

• Add support for unpacking in comprehensions (PEP 798) and for lazy imports (PEP 810), both new syntactic features in Python 3.15 (#5048)
• Python 3.15 is now supported. Compiled wheels are not yet provided for Python 3.15, so performance may be slower than on existing Python versions. Wheels will be provided once Python 3.15 is later in its release cycle. (#5127)

Stable style

• Fix # fmt: skip being ignored in nested if expressions with parenthesized in clauses (#4903)
• Add syntactic support for Python 3.15 (#5048)
• Fix crash when an f-string follows a # fmt: off comment inside brackets (#5097)
• Preserve multiline compound statement headers when # fmt: skip is placed on the colon line (#5117)

Preview style

• Improve heuristics around whether blank lines should appear before, within and after groups of same-name decorated functions (such as @overload groups) in .pyi stub files (#5021)
• Fix blank lines being removed between a function and a decorated class in .pyi stub files (#5092)
• Prevent string merger from creating unsplittable long lines when a pragma comment (e.g. # type: ignore) follows the closing bracket (#5096)

Packaging

• Run CI on 3.15 (#5127)

... (truncated)

Commits

• 87928e6 Prepare release 26.5.1 (#5140)
• c970a49 Preserve comments before fmt: skip lines (#5139)
• 5809338 Preserve inline comments inside annotation subscripts (#5130)
• 61361b7 docs: add Neovim integration guide and fix http link (#5124)
• ebe6018 CI Hotfixes (#5136)
• 9cbd95f Fix publish binaries again on Windows (#5134)
• 3dc8e6c Add new changelog (#5132)
• 6d0fff0 Fix publish binaries workflow (#5133)
• d2490e2 Prepare release 26.5.0 (#5131)
• 2b13ea7 Preserve multiline headers with fmt skip (#5117)
• Additional commits viewable in compare view