Copy contribution documentation from docs-builder to contribute-docs/contribute/.
Includes guides for local and web-based contribution, how-to guides for moving
files and redirects, and comprehensive cumulative documentation guidance.

Changes from original:
- Update absolute paths to relative paths for new location
- Add link to documentation tools in locally.md prerequisites
- Simplify on-the-web.md and add detailed GitHub editing steps
- Add legacy docs reference in on-the-web.md
- Fix cumulative docs link path in locally.md
- Update "See" to "refer to" throughout
- Remove branching strategy references (not migrated)
- Remove development section reference (not migrated)
- Update navigation title for contribute index
- Clean up local preview section wording

Create new tools.md page documenting helpful authoring tools including
the Elastic Docs VS Code extension. Includes animated demo and installation
instructions.

Features:
- VS Code extension description with key capabilities
- Availability in desktop and web editors (Codespaces, github.dev)
- Links to VS Code Marketplace and GitHub
- Screenshot showing extension in action

Create dedicated page for contributing to elastic.co/guide (legacy AsciiDoc
documentation). Consolidates legacy docs contribution information from
contribute index and on-the-web pages.

Includes:
- Overview of legacy documentation system and covered versions
- Web-based contribution workflow
- Local contribution guidance
- Cross-system update workflow using pandoc

Create index page for how-to section organizing practical guides for
common documentation tasks including moving files, setting up redirects,
and writing cumulative documentation.

Update main landing page to link to newly migrated content:
- Link to local syntax guide instead of external docs-builder
- Link to local contribution guide instead of external docs-builder
- Link to local legacy docs guide instead of external docs-builder

Provides clear entry points for all documentation systems.

Add syntax guide and contribution guides sections to toc.yml.
Organizes migrated content into logical hierarchy:

- Syntax guide with 37 markdown files
- Contribution guides organized by workflow (local, web, legacy)
- Documentation tools page
- How-to guides subsection with cumulative docs, file moves, and redirects

Change tools.mdd# to tools.md#vs-code-extension

- Copy shared _snippets folder from docs-builder
- Fix absolute paths (/syntax/, /contribute/) to relative paths
- Fix snippet includes to use correct relative paths
- Remove broken link to configure/content-set, link to external docs-builder instead
- Update configure/site reference to external docs-builder guide

These changes resolve path errors from moving content into contribute-docs.

- Use absolute paths (/contribute-docs/) for all cross-references
- Fix malformed relative paths (../syntax../, ../../.., etc)
- Escape substitution variables in example table with backticks

All 24 errors now resolved.

- Fix snippet includes in csv-include.md and reference.md to use absolute paths
- Fix malformed ../../../contribute-docs path to /contribute-docs
- Fix snippet reference to cumulative docs from syntax folder

Attempt to resolve remaining path errors.

Adds the tag-processing.md snippet file that was missing from the _snippets
folder. This file is referenced in cumulative-docs/index.md and is needed
for proper documentation rendering.

Updates syntax documentation to match latest docs-builder:
- Adds applies-to-admonitions.md snippet for admonitions with applies_to
- Adds applies-to-dropdowns.md snippet for dropdowns with applies_to badges
- Refactors admonitions.md and dropdowns.md to use new snippet includes

These changes align with upstream docs-builder updates made on Nov 3, 2025.

…x-guide

Removes the redundant /contribute-docs/contribute/ nesting by moving all
contribution guide files up one level to /contribute-docs/. This simplifies
URLs and makes the structure more intuitive.

Changes:
- Renamed contribute/index.md to contribute-index.md
- Moved all contribute/* files to contribute-docs/ root
- Moved contribute/how-to/ to contribute-docs/how-to/
- Moved contribute/_snippets/ to _snippets-contribute/
- Moved contribute/images/ to contribute-docs/images/
- Updated toc.yml to reflect flattened structure
- Updated all internal links throughout documentation

URLs before:
- /contribute-docs/contribute/locally
- /contribute-docs/contribute/how-to/move

URLs after:
- /contribute-docs/locally
- /contribute-docs/how-to/move