fix: include identifier before cursor in definition request

The watchdog definition request already does this correctly, but when the request falls through to the file worker, it wouldn't use the identifier before the cursor.

src/Lean/Server/FileWorker/RequestHandling.lean

@@ -223,7 +223,7 @@ def handleDefinition (kind : GoToKind) (p : TextDocumentPositionParams)
   let text := doc.meta.text
   let hoverPos := text.lspPosToUtf8Pos p.position
 
-  withWaitFindSnap doc (fun s => s.endPos > hoverPos)
+  withWaitFindSnap doc (fun s => s.endPos >= hoverPos)
     (notFoundX := pure #[]) fun snap => do
       if let some infoWithCtx := snap.infoTree.hoverableInfoAt? (omitIdentApps := true) (includeStop := true /- #767 -/) hoverPos then
         locationLinksOfInfo kind infoWithCtx snap.infoTree