runtime: amend doc for setPinned

Author: callthingsoff

src/runtime/pinner.go

@@ -143,8 +143,8 @@ func isPinned(ptr unsafe.Pointer) bool {
 }
 
 // setPinned marks or unmarks a Go pointer as pinned, when the ptr is a Go pointer.
-// It will be ignored while try to pin a non-Go pointer,
-// and it will be panic while try to unpin a non-Go pointer,
+// It will be ignored while trying to pin a non-Go pointer.
+// It will panic while trying to unpin a non-Go pointer,
 // which should not happen in normal usage.
 func setPinned(ptr unsafe.Pointer, pin bool) bool {
 span := spanOfHeap(uintptr(ptr))