go/ssa: updated inconsistent docs after Program.Method rename

Fixes golang/go#20225

Change-Id: Ifd069546698981f3c6a3673dd73a1bd770560f8b
Reviewed-on: https://go-review.googlesource.com/c/42570
Reviewed-by: Alan Donovan <adonovan@google.com>
diff --git a/go/ssa/ssa.go b/go/ssa/ssa.go
index 7f7998a..78272c5 100644
--- a/go/ssa/ssa.go
+++ b/go/ssa/ssa.go
@@ -654,7 +654,7 @@
 // value of a concrete type.
 //
 // Use Program.MethodSets.MethodSet(X.Type()) to find the method-set
-// of X, and Program.Method(m) to find the implementation of a method.
+// of X, and Program.MethodValue(m) to find the implementation of a method.
 //
 // To construct the zero value of an interface type T, use:
 // 	NewConst(constant.MakeNil(), T, pos)