ace2_inner: Fix efficiency of `rangeForLine()`
ace2_inner: Fix efficiency of `rangeForLine()`

Returning `true` or `false` has no effect when iterating using
`Array.prototype.forEach`. This fixes a bug introduced in commit
b28bfe8e31cf4a95b1242bc35b47201f7560a0a3.

ether/etherpad-lite,ether/etherpad-lite,ether/etherpad-lite