[C++][Doc] Document supported Parquet features

[asfimport]

We should document the Parquet features supported by our C++ implementation.

Reporter: Antoine Pitrou / @pitrou
Assignee: Antoine Pitrou / @pitrou

Related issues:

• [C++] Add Parquet docs (relates to)
• [Doc][C++] Document supported Parquet encryption features (is related to)

PRs and other links:

• GitHub Pull Request #8928

_{Note: This issue was originally created as ARROW-10918. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
Issue resolved by pull request 8928
#8928