docs: Remove type completions from release note

We're not going to include Scala3 type completion to
Metals release note.

Context:
#4236
#4234 (comment)

> Context: #4234 (comment) we encounter some regressions related to the
> type completions feature.
> We revert those changes because we're going to release a new version of Metals,
> and it would be safer not to include those features in the new release #4214

website/blog/2022-08-08-aluminium.md

@@ -45,7 +45,6 @@ the community.
 Check out [https://scalameta.org/metals/](https://scalameta.org/metals/), and
 give Metals a try!
 
-- [Scala 3] Type completion
 - [Scala 3] Auto import and completion for extension methods
 - [Scala 3] Convert to Named Parameters code action
 - [Scala 3] Scaladoc Completion for Scala3
@@ -57,14 +56,6 @@ give Metals a try!
 
 and a lot of bugfixes!
 
-## [Scala 3] Type Competion
-
-![type-completion](https://i.imgur.com/7kDzoLs.gif)
-
-This newly implemented feature for Scala 3 is not only adding necessary `[]` and `{}` suffixes to type completions; but also filtering out some of the invalid completion results.
-
-As this is a new feature, please let us know if you encounter any missing or invalid results by opening an issue.
-
 ## [Scala 3] Auto import and completion for extension methods
 
 You might know that Scala 3 has introduced `extension methods` that allow defining new methods to your existing types.