refactor: Remove decoration protocol

architecture.md

@@ -70,14 +70,11 @@ Metals communicates with build server such as `bloop` and `sbt` using [Build Ser
 
 For more details about sbt's BSP support in Metals, see [the blog post](https://scalameta.org/metals/blog/2020/11/06/sbt-BSP-support/).
 
-## Worksheet
+## Worksheets
 
 Worksheet support is provided by [mdoc](https://github.com/scalameta/mdoc), which is able to typecheck and evaluate each line of the input. The main class responsible for worksheets is [WorksheetProvider.scala](https://github.com/scalameta/metals/blob/main/metals/src/main/scala/scala/meta/internal/worksheets/WorksheetProvider.scala). It is responsible for downloading mdoc instance for each Scala version that is supported and running the evaluation in the file input.
 
-Later the evaluations are published using [decoration extension](https://scalameta.org/metals/docs/integrations/decoration-protocol) or via additional Text Edits for editors that do not support decorations. This is done in the two classes implementing [WorksheetPublisher.scala](https://github.com/scalameta/metals/blob/main/metals/src/main/scala/scala/meta/internal/worksheets/WorksheetPublisher.scala):
-
-- [DecorationWorksheetPublisher.scala](https://github.com/scalameta/metals/blob/main/metals/src/main/scala/scala/meta/internal/worksheets/DecorationWorksheetPublisher.scala) for decoration publishing
-- [WorkspaceEditWorksheetPublisher.scala](https://github.com/scalameta/metals/blob/main/metals/src/main/scala/scala/meta/internal/worksheets/WorkspaceEditWorksheetPublisher.scala) for publishing decorations as comments in the code
+Later the evaluations are published using [inlay hints](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_inlayHint).
 
 ## Formatting
 

docs/editors/overview.md

@@ -357,13 +357,7 @@ projects.
 
 ## Worksheets
 
-**✅**: Worksheets work via the Decoration protocol and are added as a
-non-editable side decoration.
-
-**Comments**: Worksheets work via `workspace/applyEdit` by adding comments to
-the source code and support hover to show larger output. You can find more
-information about worksheets under the editor specific worksheet section. For
-example, [here for VS Code](vscode.md#worksheets).
+**✅**: Worksheets work via inlay hints.
 
 By default there is a 30 second timeout on worksheet evaluation, this setting can be overridden by `-Dmetals.worksheet-timeout=<number of seconds>` server property.
 
@@ -448,9 +442,6 @@ website.
 
 **Status bar**: Editor client implements the `metals/status` notification.
 
-**Decoration protocol**: Editor client implements the
-[Decoration Protocol](../integrations/decoration-protocol.md).
-
 **Tree view**: Editor client implements the
 [Tree View Protocol](../integrations/tree-view-protocol.md).
 

docs/integrations/new-editor.md

@@ -101,8 +101,6 @@ The currently available settings for `InitializationOptions` are listed below.
         snippetAutoIndent?: boolean;
       }
       debuggingProvider?: boolean;
-      decorationProvider?: boolean;
-      inlineDecorationProvider?: boolean;
       didFocusProvider?: boolean;
       doctorProvider?: "json" | "html";
       executeClientCommandProvider?: boolean;
@@ -230,13 +228,6 @@ Boolean value to signify that the client supports the
 
 Default value: `false`
 
-##### `decorationProvider`
-
-Boolean value to signify that the client supports the
-[Decoration Protocol](../integrations/decoration-protocol.md).
-
-Default value: `false`
-
 ##### `didFocusProvider`
 
 Boolean value to signify that the client supports the
@@ -289,13 +280,6 @@ Possible values:
   For example, `C:\Users\IEUser\workspace\project/*.{scala,sbt,properties}`.
   This mode is used by the VS Code client.
 
-##### `inlineDecorationProvider`
-
-If the client implements the Metals Decoration Protocol **and** supports
-decorations to be shown inline and not only at the end of a line.
-
-Default: `false`
-
 ##### `icons`
 
 Possible values:
@@ -696,11 +680,6 @@ Metals implements several custom JSON-RPC endpoints related to rendering tree
 views in the editor client, the
 [Tree View Protocol](../integrations/tree-view-protocol.md).
 
-### Decoration Protocol
-
-Metals implements an LSP extension to display non-editable text in the editor,
-see the [Decoration Protocol](../integrations/decoration-protocol.md).
-
 ### `metals/status`
 
 The Metals status notification is sent from the server to the client to notify

metals-docs/src/main/scala/docs/WorksheetModifier.scala

@@ -16,8 +16,8 @@ class WorksheetModifier extends StringModifier {
 
     val (howYouSeeEvaluations, howToHover) = info match {
       case "vscode" =>
-        "as a decoration at the end of the line." ->
-          "hover on the decoration to expand the decoration."
+        "as a inlay hint at the end of the line." ->
+          "hover on the inlay hint to expand it."
       case _ =>
         "as a comment as the end of the line." -> "hover on the comment to expand."
     }

metals/src/main/scala/scala/meta/internal/metals/ClientConfiguration.scala

@@ -144,16 +144,6 @@ final class ClientConfiguration(
   def isRunProvider(): Boolean =
     initializationOptions.runProvider.getOrElse(false)
 
-  def isDecorationProvider(): Boolean =
-    extract(
-      initializationOptions.decorationProvider,
-      experimentalCapabilities.decorationProvider,
-      false,
-    )
-
-  def isInlineDecorationProvider(): Boolean =
-    initializationOptions.inlineDecorationProvider.getOrElse(false)
-
   def isInlayHintsEnabled(): Boolean = {
     for {
       capabilities <- clientCapabilities

metals/src/main/scala/scala/meta/internal/metals/ClientExperimentalCapabilities.scala

@@ -15,6 +15,7 @@ import org.eclipse.{lsp4j => l}
  */
 final case class ClientExperimentalCapabilities(
     debuggingProvider: Option[Boolean],
+    @deprecated("Decoration protocol is no longer used.")
     decorationProvider: Option[Boolean],
     didFocusProvider: Option[Boolean],
     doctorProvider: Option[String],

metals/src/main/scala/scala/meta/internal/metals/InitializationOptions.scala

@@ -54,7 +54,9 @@ final case class InitializationOptions(
     compilerOptions: CompilerInitializationOptions,
     debuggingProvider: Option[Boolean],
     runProvider: Option[Boolean],
+    @deprecated("Decoration protocol is no longer used.")
     decorationProvider: Option[Boolean],
+    @deprecated("Decoration protocol is no longer used.")
     inlineDecorationProvider: Option[Boolean],
     didFocusProvider: Option[Boolean],
     doctorProvider: Option[String],