docs(syntax): document local code directives

[kadymov]

Summary

• document local {% code %} file inclusion in Russian and English
• describe path resolution, lang, numeric and marker ranges, and keep-indents
• document fallback behavior, build errors, and unsupported external sources

Testing

• built the complete documentation repository with the CLI from feat(cli): support local code directives cli#2259
• git diff --check

Related

• DOCSTOOLS-6666
• Depends on feat(cli): support local code directives cli#2259
• Related to Встраивание файлов из внешних источников ({% include-code %}) cli#2207 and feat(build): include code from external sources cli#2209

[github-actions]

✅ Documentation build

Revision built successfully
Revision preview link

Build logs

Warnings (2)

⚠️ en/guides/openapi.md: 168: YFM001 / inline-code-length Inline code length [Expected: 100; Actual: 265] [Context: " — the specification is displayed directly on the page (default value). If the size of the specification's json schema exceeds the value of ##maxOpenapiIncludeSize## (100 KB by default), the mode automatically switches to "]

⚠️ en/tools/docs/build.md: 52: YFM001 / inline-code-length Inline code length [Expected: 100; Actual: 109] [Context: " — a snapshot of the dependency graph (pages, included files, assets, missing paths, edge count), as well as "]