unicode/rangetable: Add key name when initializng Range16 and Range32.

GAE explicitly rejects unkeyed struct initialization. See similar discussion for net/mail:
https://groups.google.com/forum/#!topic/golang-nuts/2ShgtUHsdqY

Change-Id: I9ce1913fc4fc76e4b10b0a11dc49c03e5d1039b0
Reviewed-on: https://go-review.googlesource.com/12020
Reviewed-by: Nigel Tao <nigeltao@golang.org>
diff --git a/unicode/rangetable/rangetable.go b/unicode/rangetable/rangetable.go
index 2b2c3fd..187882c 100644
--- a/unicode/rangetable/rangetable.go
+++ b/unicode/rangetable/rangetable.go
@@ -31,9 +31,9 @@
 	var rt unicode.RangeTable
 	for _, r := range r[:k] {
 		if r <= 0xFFFF {
-			rt.R16 = append(rt.R16, unicode.Range16{uint16(r), uint16(r), 1})
+			rt.R16 = append(rt.R16, unicode.Range16{Lo: uint16(r), Hi: uint16(r), Stride: 1})
 		} else {
-			rt.R32 = append(rt.R32, unicode.Range32{uint32(r), uint32(r), 1})
+			rt.R32 = append(rt.R32, unicode.Range32{Lo: uint32(r), Hi: uint32(r), Stride: 1})
 		}
 	}