fix: add capability for "open cargo.toml" lsp extension

crates/rust-analyzer/src/caps.rs

@@ -114,6 +114,7 @@ pub fn server_capabilities(config: &Config) -> ServerCapabilities {
         moniker_provider: None,
         experimental: Some(json!({
             "joinLines": true,
+            "openCargoToml": true,
             "ssr": true,
             "onEnter": true,
             "parentModule": true,

docs/dev/lsp-extensions.md

@@ -619,6 +619,8 @@ Such actions on the client side are appended to a hover bottom as command links:
 
 **Issue:** https://github.com/rust-analyzer/rust-analyzer/issues/6462
 
+**Experimental Server Capability:** `{ "openCargoToml": boolean }`
+
 This request is sent from client to server to open the current project's Cargo.toml
 
 **Method:** `experimental/openCargoToml`