[Docs][MATLAB] Rename `arrow.recordbatch` (all lowercase) to `arrow.recordBatch` (camelCase)

[kevingurney]

Describe the enhancement requested

As @kou suggested in #37215 (comment), it makes sense to rename arrow.recordbatch (all lowercase) to arrow.recordBatch (camelCase).

recordBatch is the first "two-word" function in the top-level arrow.* package, so it makes sense to establish a clear camelCase standard for "multi-word" functions in the MATLAB interface at this point.

One part of the rationale motivating this change is that other language bindings follow a similar pattern (e.g. pyarrow.record_batch instead of pyarrow.recordbatch).

Component(s)

MATLAB

[kevingurney]

Added label Component: documentation since making this change requires updating the MATLAB README.md to reflect arrow.recordbatch being renamed to arrow.recordBatch.