ru: fix 25 factually wrong fuzzy entries

[yabanci]

This PR fixes a narrow set of po/ru.po entries where the existing fuzzy translation is factually wrong — different concept, swapped link, wrong day number, broken markdown, etc. — not where it's merely stylistically outdated. The other ~50 fuzzy entries are left with their #, fuzzy flag untouched for @baltuky (the original translator) to revisit on their own pace.

Scope

Wrong chapter titles in SUMMARY

msgid	was	now
Associated Types	Скалярные типы	Ассоциированные типы
Shared Types (C++ interop)	Скалярные типы	Общие типы
Try Conversions	Неявные преобразования	Преобразования через Try
Marker Traits	Небезопасные типажи	Маркерные типажи
Shared References	Заимствование (= different section)	Общие ссылки

msgmerge nearest-match garbage. Six chapter-link entries had been overwritten with the recurring "Больше информации об использовании шаблонов..." boilerplate or with an unrelated link — replaced with correct ones: [Static], [Pattern Matching], [Matching Values], [Deriving], [Strings], [Marker Traits] (which pointed at the Arrays link).

Wrong body translations

• Native support for Rust slices in C++ → was "Встроенная поддержка тестирования" (slices ≠ testing)
• `while let` expressions and `let else` expressions → both were "Выражение if let"
• while-let (anchor) → was "Выражение while let" (anchor name vs section title)
• Lives for the entire duration of the program → was "Функция main является точкой входа в программу"
• Storing Books → was "Строки" (Books ≠ Strings)
• An exercise on pattern matching. → was about enums + pattern matching
• Welcome to Day 4 → was "Добро пожаловать в День 1"
• Can be scaled down to very constrained devices such as microcontrollers. → was "...мобильные телефоны" (microcontrollers ≠ phones)
• Some things to try: → was "Примечания:" (notes ≠ things to try)

Wrong code literals

• "Welcome to RustOS 3.14" → was "Добро пожаловать в День 1"
• "Hello " → was "Привет, мир!" (different literal)

Broken markdown links (literally not rendering as links)

• Two After looking at the exercises... [solutions](solutions-*.md) entries had \\[solutions\\] with escaped brackets and no working link target.

Terminology

Followed the existing glossary in ru.po (Trait → Типаж, Borrow → Заимствование, Closure → Замыкание, Slice → Срез, Lifetime → Время жизни) and the established RU Rust canon for the new replacements (Marker Traits → Маркерные типажи; #[derive] → Вывод типажей). Shared/Exclusive References intentionally kept as Общие/Эксклюзивные ссылки, matching the modern shared/exclusive terminology that this course uses (not the older immutable/mutable framing) — happy to switch if reviewers prefer the canonical RU Book "неизменяемые/изменяемые".

Verification

$ msgfmt --statistics -o /dev/null po/ru.po
574 translated messages, 50 fuzzy translations, 3136 untranslated messages.

(Before: 552 translated, 72 fuzzy, 3136 untranslated. Δ = +22 translated, −22 fuzzy.)

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[yabanci]

@googlebot I signed it!

[yabanci]

Hi @baltuky — gentle ping on this one. The CLA is signed and CI is green.

Scope is deliberately small: only the 25 fuzzy entries where the existing translation was factually wrong. The other fuzzy entries I left flagged for you, since stylistic preference isn't enough reason to overwrite your work.

If you get a chance to take a look, I'd appreciate it. I also opened #3185 (types-and-values segment) as a follow-up. Happy to adjust anything to match your glossary. Thanks!