draw: fix a comment typo.

Change-Id: I6d34d091514915333e488cee9e2ddb5a9d78b6a5
Reviewed-on: https://go-review.googlesource.com/6801
Reviewed-by: David Symonds <dsymonds@golang.org>
diff --git a/draw/scale.go b/draw/scale.go
index 9f8cdd4..a603d80 100644
--- a/draw/scale.go
+++ b/draw/scale.go
@@ -23,7 +23,7 @@
 }
 
 // Interpolator is an interpolation algorithm, when dst and src pixels don't
-// have a 1:1 correspondance.
+// have a 1:1 correspondence.
 //
 // Of the interpolators provided by this package:
 //	- NearestNeighbor is fast but usually looks worst.