fix(new): Add to workspace relative to manifest, not current-dir

We were correctly doing this for cases like `cargo new foo` or
`cargo new deeper/than/this/directory/foo` but not `cargo new ../foo`.

This came up when discussing rust-lang#14501

src/cargo/ops/cargo_new.rs

@@ -802,7 +802,7 @@ fn mk(gctx: &GlobalContext, opts: &MkOptions<'_>) -> CargoResult<()> {
         }
     }
 
-    let manifest_path = path.join("Cargo.toml");
+    let manifest_path = paths::normalize_path(&path.join("Cargo.toml"));
     if let Ok(root_manifest_path) = find_root_manifest_for_wd(&manifest_path) {
         let root_manifest = paths::read(&root_manifest_path)?;
         // Sometimes the root manifest is not a valid manifest, so we only try to parse it if it is.

tests/testsuite/cargo_new/ignore_current_dir_workspace/out/workspace/Cargo.toml

@@ -1,5 +1,4 @@
 [workspace]
-members = ["../out-of-workspace"]
 
 [package]
 name = "foo"