exp/typeparams: remove caveat around usage

This has had enough time to soak for feedback. If we need further
changes, we can make them additive.

Fixes golang/go#50447

Change-Id: Ie93c32f4c077277bcc60167b919028fee4fc7c23
Reviewed-on: https://go-review.googlesource.com/c/exp/+/391674
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>
diff --git a/typeparams/common.go b/typeparams/common.go
index e697083..0193388 100644
--- a/typeparams/common.go
+++ b/typeparams/common.go
@@ -5,10 +5,6 @@
 // Package typeparams contains common utilities for writing tools that interact
 // with generic Go code, as introduced with Go 1.18.
 //
-// THIS PACKAGE IS CURRENTLY EXPERIMENTAL AND MAY CHANGE. While the API is
-// being tested, we may find the need for improvement. This caveat will be
-// removed shortly.
-//
 // Many of the types and functions in this package are proxies for the new APIs
 // introduced in the standard library with Go 1.18. For example, the
 // typeparams.Union type is an alias for go/types.Union, and the ForTypeSpec