Correctly declare support for "workspace/willRenameFiles".

[rgrunber]

@angelozerr , can you verify this change fixes things for you ? I also would need to adjust vscode-java as it appears to break it by sending a duplicate workspace/willRenameFiles, which causes some problems. Basically that client doesn't want the renames to be applied immediately, but rather get the edits and allow a user to apply/discard them.

• The server capabilities in the initialize response must contain a "willRename" object in the workspace's "fileOperations" object.
• Fixes JDT LS should mention as capability that it can support willRenameFiles #3126

--- old.txt 2024-04-05 11:22:47.101634192 -0400
+++ new.txt 2024-04-05 11:31:28.769420565 -0400
@@ -1,4 +1,4 @@
-[Trace - 11:22:11] Received response 'initialize - (0)' in 5456ms.
+[Trace - 11:31:03] Received response 'initialize - (0)' in 6603ms.
 Result: {
     "capabilities": {
         "textDocumentSync": {
@@ -14,6 +14,19 @@
             "workspaceFolders": {
                 "supported": true,
                 "changeNotifications": true
+            },
+            "fileOperations": {
+                "willRename": {
+                    "filters": [
+                        {
+                            "pattern": {
+                                "glob": "**/*.java",
+                                "matches": "file"
+                            },
+                            "scheme": "file"
+                        }
+                    ]
+                }
             }
         },
         "callHierarchyProvider": true,

[mikehaertl]

@rgrunber If I read this correctly this change now reports a filter back to the client that restricts willRename operations to **/*.java files. It seems this prevents package rename operations in some clients now as the filter excludes directories. At least that's what I see in neovim with nvim-lsp-file-operations. I just started using this, though, so not sure if it worked before.

From the tests it seems that renaming a package should work:

eclipse.jdt.ls/org.eclipse.jdt.ls.tests/src/org/eclipse/jdt/ls/core/internal/handlers/FileEventHandlerTest.java

Lines 142 to 144 in bb26c98

	// Test renaming package from "parent.pack2" to "parent.newpack2"
	@Test
	public void testRenamePackage() throws JavaModelException, BadLocationException {