syscall: remove deprecation notice

The syscall package isn't getting new system call support,
but it is not deprecated.

Fixes #60797

Change-Id: I33b60269f9ce70ac2108fa0f3d42fd87a3076bf1
Reviewed-on: https://go-review.googlesource.com/c/go/+/520018
Run-TryBot: Ian Lance Taylor <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

Author: ianlancetaylor

src/syscall/syscall.go

@@ -18,11 +18,11 @@
 // err is an operating system error describing the failure.
 // On most systems, that error has type syscall.Errno.
 //
-// Deprecated: this package is locked down. Callers should use the
-// corresponding package in the golang.org/x/sys repository instead.
-// That is also where updates required by new systems or versions
-// should be applied. See https://golang.org/s/go1.4-syscall for more
-// information.
+// NOTE: Most of the functions, types, and constants defined in
+// this package are also available in the [golang.org/x/sys] package.
+// That package has more system call support than this one,
+// and most new code should prefer that package where possible.
+// See https://golang.org/s/go1.4-syscall for more information.
 package syscall
 
 import "internal/bytealg"