[Format] Confusing array length description

[asfimport]

"To encourage developers to compose smaller arrays (each of which contains contiguous memory in its leaf nodes) to create larger array structures possibly exceeding 2^31 - 1 elements, as opposed to allocating very large contiguous memory blocks."

I think it could use a little more verbose explanation: to compose smaller arrays to create larger array structures

Reporter: Krisztian Szucs / @kszucs
Assignee: Uwe Korn / @xhochy

_{Note: This issue was originally created as ARROW-2475. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
What do you find confusing exactly? Feel free to submit a PR making the text clearer.

[asfimport]

Krisztian Szucs / @kszucs:
I'm not sure that I can distinguish between array and array structure.

Is an array structure is a structure which contains multiple arrays (like ChunkedArray)?
As opposed to allocating very large contiguous memory blocks in a single array (but not array structure)?

[asfimport]

Francois Saint-Jacques / @fsaintjacques:
I think adding array structure, i.e. ChunkedArray, ...` would remove any confusion.

[asfimport]

Wes McKinney / @wesm:
Maybe "array-like data structure" would be more specific than "array structure"

[asfimport]

Wes McKinney / @wesm:
I'll take care of this as soon as #2856 is addressed

[asfimport]

Wes McKinney / @wesm:
This was addressed already since the docs were merged