[Format] Missing documentation under Dictionary encoding section on MetaData page

[asfimport]

First time throwing up an issue here so let me know if there's anything I missed / more details I can provide.

Just going through the arrow documentation at https://arrow.apache.org/docs/python/ and I noticed that there's a section that is currently blank. From what I can tell the section https://arrow.apache.org/docs/format/Metadata.html#dictionary-encoding currently contains nothing in it. Is that intended? It was confusing to see a blank section, but that is just my opinion so it may not be worth changing.

If this is something work fixing / improving, then it's probably worth either filling out that section or simply removing header to avoid future confusion.

Reporter: Lennox Stevenson
Assignee: Wes McKinney / @wesm

_{Note: This issue was originally created as ARROW-5211. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
Yes, it should be filled out

[asfimport]

Wes McKinney / @wesm:
Resolved in 67d46c7

[asfimport]

Lennox Stevenson:
Thanks for doing this Wes, much appreciated!