Fix wording in is{less,greater}than for string comparison.

Was previously ambiguous (our strcmp(), an equality test, or C's,
reporting ordering) and poorly phrased (what does "identical to" mean
when we're returning a boolean and strcmp is returning a sign ?), so
rephrased to make it explicit.
Bad phrasing in getindices() doc.

It's order of the list that's not specified; not the order of the
order of the list !  Also, flow long line.
Attempt to explain how getindices() handles multi-indexed arrays.
Merge pull request #891 from ediosyncratic/petty-fixes

Petty fixes to documentation