ja: read a leading minus as マイナス

[yasumorishima]

Third of the small PRs from #715, independent of #720 and #721.

What is wrong

A unary + or - was spoken 正の / 負の. Those name a kind of number — 負の数 is "the negative numbers" as a category — and they are not how −5 is read aloud. Japanese reads it マイナス 5, using the same word as the binary operator; there is no separate "negative" word the way English distinguishes "negative five" from "five minus".

The reference this series follows agrees: its worked example reads −b as 「マイナス b」, and the symbol table in its appendix gives ± as 「プラス・オア・マイナス」. 負の does not appear anywhere in it.

山口雄仁・川根深・澤崎陽彦「日本語による数式読み上げ法の基本構成について」日本数学教育学会誌 78(9), 239–247 (1996)

Changes

Three pairs in ClearSpeak_Rules.yaml — the two PosNegSqRoot rules and negative_and_positive — and the prefix= forms of plus and minus in definitions.yaml.

Deliberately not touched: SharedRules/general.yaml, where 正の / 負の are correct. There they modify 整数 in "the set of all positive integers", which is exactly the categorical sense that makes them wrong as a reading of −5. A blanket replacement would have broken that, so the patch asserts that file is unchanged.

Tests

negative_number (−5 → 「マイナス 5」) in both styles.

Related

This is what #721 left out. There, x⁻² came out as 「x の 負の 2 乗」; with this change it reads 「x の マイナス 2 乗」. I did not add that test to either PR because it needs both changes; it belongs in whichever of the two merges second, or in a follow-up.

Also spotted while here, for a later PR rather than this one: general.yaml renders ℂ as 「複雑な数字」 ("complicated numbers") and ℕ as 「自然な数字」. The mathematical terms are 複素数 and 自然数.