Add back sysroot-abi feature gate to rust-analyzer

Author: lnicola

Cargo.lock

@@ -68,6 +68,7 @@ ide-db.workspace = true
 ide-ssr.workspace = true
 ide.workspace = true
 proc-macro-api.workspace = true
+proc-macro-srv-cli.workspace = true
 profile.workspace = true
 project-model.workspace = true
 stdx.workspace = true
@@ -94,4 +95,5 @@ mbe.workspace = true
 [features]
 jemalloc = ["jemallocator", "profile/jemalloc"]
 force-always-assert = ["always-assert/force"]
-in-rust-tree = ["ide/in-rust-tree", "syntax/in-rust-tree"]
+sysroot-abi = ["proc-macro-srv-cli/sysroot-abi"]
+in-rust-tree = ["sysroot-abi", "ide/in-rust-tree", "syntax/in-rust-tree"]