docs: fix links between docs pages

[dolfim-ibm]

Fixing some broken links between docs pages (from mkdocs warnings).

Checklist:

• Documentation has been updated, if necessary.
• Examples have been added, if necessary.
• Tests have been added, if necessary.

[mergify]

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🟢 Enforce conventional commit

Wonderful, this rule succeeded.

Make sure that we follow https://www.conventionalcommits.org/en/v1.0.0/

• title ~= ^(fix|feat|docs|style|refactor|perf|test|build|ci|chore|revert)(?:\(.+\))?(!)?:

[vagenas]

Based on https://ds4sd.github.io/docling/concepts/chunking/ both updated links appear to be working.
So maybe they are broken when navigating the raw .md files on GitHub, but if I recall correctly, setting them to the .md counterpart breaks the rendered docs.

[dolfim-ibm]

Here are the mkdocs messages

INFO    -  Doc file 'v2.md' contains an unrecognized relative link '../examples/run_with_formats/', it was left as is.
INFO    -  Doc file 'v2.md' contains an unrecognized relative link '../examples/custom_convert/', it was left as is.
INFO    -  Doc file 'v2.md' contains an unrecognized relative link '../usage/#chunking', it was left as is. Did you mean 'usage.md#chunking'?
INFO    -  Doc file 'concepts/chunking.md' contains an unrecognized relative link '../../examples/hybrid_chunking', it was left as is.
INFO    -  Doc file 'concepts/chunking.md' contains an unrecognized relative link '../docling_document', it was left as is. Did you mean
           'docling_document.md'?

[vagenas]

... but if I recall correctly, setting them to the .md counterpart breaks the rendered docs.

In the past I was experiencing issues like the ones described here, but now I checked and it works, so approving.