all: use "reports whether" in place of "returns true if(f)"

Comment changes only.

Change-Id: I56848814564c4aa0988b451df18bebdfc88d6d94
Reviewed-on: https://go-review.googlesource.com/7721
Reviewed-by: Rob Pike <r@golang.org>

src/path/path.go

@@ -192,7 +192,7 @@ func Base(path string) string {
 	return path
 }
 
-// IsAbs returns true if the path is absolute.
+// IsAbs reports whether the path is absolute.
 func IsAbs(path string) bool {
 	return len(path) > 0 && path[0] == '/'
 }