「キーワード引数」を「名前付き引数」に修正

[ultimatile]

fix #288

[Copilot]

Pull Request Overview

This PR corrects Japanese terminology by replacing "キーワード引数" (keyword arguments) with "名前付き引数" (named arguments) in the documentation to address issue #288.

• Updates terminology from "keyword arguments" to "named arguments" in Japanese documentation
• Changes are made in both math library documentation and function documentation

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
docs/reference/library/math.md	Updates terminology in the math library documentation section about function calls
crates/typst-library/src/foundations/func.rs	Updates terminology in the function documentation comments

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