Consider renaming SVGPathElement::getPathSegmentAtLength() to getPathSegmentAtDistance() #1218

Some initial feedback from part of the W3C TAG on getPathSegementAtLength():

Generally, "length" refers to the total length of the list, and we use ...At(...) for functions that index into the list. When we need a name for the index, it's "index", not "length". I see that this function isn't treating the path as an array of elements, so ...At(...) would probably be confusing, but I think AtLength() will also be confusing.

What about getPathSegmentAtDistance()?

The current name, getPathSegmentAtLength(), is consistent with another method on the path element: getPointAtLength(). According to MDN, getPointAtLength() has been shipping in all browsers for a long time.