reflect: fix doc string

Fixes golang#12017.

Change-Id: I3dfcf9d0b62cae02eca1973383f0aad286a6ef4d
Reviewed-on: https://go-review.googlesource.com/13136
Reviewed-by: Keith Randall <khr@golang.org>

src/reflect/value.go

@@ -281,7 +281,7 @@ func (v Value) CanAddr() bool {
 // A Value can be changed only if it is addressable and was not
 // obtained by the use of unexported struct fields.
 // If CanSet returns false, calling Set or any type-specific
-// setter (e.g., SetBool, SetInt64) will panic.
+// setter (e.g., SetBool, SetInt) will panic.
 func (v Value) CanSet() bool {
 	return v.flag&(flagAddr|flagRO) == flagAddr
 }