Update contributing doc to reflect window/progress title name change

 - Updates the docs to reflect the name changes made in 9a298c1

Author: Lucas Bullen

contributing.md

@@ -306,14 +306,14 @@ The RLS uses some custom extensions to the Language Server Protocol.
 These are all sent from the RLS to an LSP client and are only used to improve
 the user experience by showing progress indicators.
 
-* `window/progress`: notification, `title: "Build"`. Sent before build starts.
-* `window/progress`: notification with `title: "Build"`, repeated for each compile target.
+* `window/progress`: notification, `title: "Building"`. Sent before build starts.
+* `window/progress`: notification with `title: "Building"`, repeated for each compile target.
   * When total amount of work is not known, has field `message` set to the current crate name.
   * When total amount of work is known, has field `percentage` set to how much of build has started.
-* `window/progress`: notification, `title: "Build"`, `"done": true`. Sent when build ends.
-* `window/progress`: notification, `title: "Diagnostics"`. Sent before analysis of build starts.
+* `window/progress`: notification, `title: "Building"`, `"done": true`. Sent when build ends.
+* `window/progress`: notification, `title: "Indexing"`. Sent before analysis of build starts.
 * ... standard LSP `publishDiagnostics`
-* `window/progress`: notification, `title: "Diagnostics"`, `"done": true`. Sent when analysis ends.
+* `window/progress`: notification, `title: "Indexing"`, `"done": true`. Sent when analysis ends.
 
 #### LSP Client to RLS