gopls/doc: update generic code section of advanced.md

Since golang.org/cl/343732 was merged the dev.typeparams branch is no
longer needed, just Go at tip.

Change-Id: Ifb2e5220bc2f544d86cfa84d43d12d93e4e7fddb
Reviewed-on: https://go-review.googlesource.com/c/tools/+/343967
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
Trust: Rebecca Stambler <rstambler@golang.org>
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
diff --git a/gopls/doc/advanced.md b/gopls/doc/advanced.md
index 0fa1139..da37494 100644
--- a/gopls/doc/advanced.md
+++ b/gopls/doc/advanced.md
@@ -41,19 +41,18 @@
 type set addendum ([golang/go#45346](https://golang.org/issues/45346)).
 
 To enable this support, you need to build gopls with a version of Go that
-supports type parameters: the
-[dev.typeparams branch](https://github.com/golang/go/tree/dev.typeparams). This
-can be done by checking out this branch in the Go repository, or by using
+supports type parameters, currently just tip. This can be done by checking
+out the `master` branch in the Go repository, or by using
 `golang.org/dl/gotip`:
 
 ```
 $ go get golang.org/dl/gotip
-$ gotip download dev.typeparams
+$ gotip download
 ```
 
 For building gopls with type parameter support, it is recommended that you
 build gopls at tip. External APIs are under active development on the
-`dev.typeparams` branch, so building gopls at tip minimizes the chances of
+Go `master` branch, so building gopls at tip minimizes the chances of
 a build failure (though it is still possible). To get enhanced gopls features
 for generic code, build gopls with the `typeparams` build constraint (though
 this increases your chances of a build failure).
@@ -63,11 +62,11 @@
 ```
 
 This will build a version of gopls that understands generic code. To actually
-run the generic code you develop, you must also tell the compiler to speak
-generics using the `-G=3` compiler flag. For example
+run the generic code you develop, you must also use the tip version of the Go
+compiler. For example:
 
 ```
-$ gotip run -gcflags=-G=3 .
+$ gotip run .
 ```
 
 [Go project]: https://go.googlesource.com/go