os: clarify that IsNotExist, IsExist, IsPermission and IsTimeout work with nil errors
Referring to these functions' parameter as "*the* error" could be taken
to imply that a non-nil error from elsewhere is expected; referring to
it as "its argument" avoids that ambiguity.
Fixes #31065
Change-Id: I117892dd53fff6f92d11a416e4abedee5d2f9337
Reviewed-on: https://go-review.googlesource.com/c/go/+/170077 Reviewed-by: Rob Pike <r@golang.org> Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Jonathan Amsterdam <jba@google.com>