fix(toml)!: Disallow [lints] in virtual workspaces

This was missed with the initial `[lints]` implementation.

While this is a breaking change, this is aligned with ones we've done in
the past.  A lot of times, we warn first.  My hope is that isn't needed
this time because
- It only exists virtual workspaces so they aren't published
- It is a nop to have this which is likely to be caught
- This is so new that the number of people using it, and likely running
  into this case, is quite low.

Author: epage

src/cargo/util/toml/mod.rs

@@ -1122,6 +1122,9 @@ fn to_virtual_manifest(
     if me.badges.is_some() {
         bail!("this virtual manifest specifies a [badges] section, which is not allowed");
     }
+    if me.lints.is_some() {
+        bail!("this virtual manifest specifies a [lints] section, which is not allowed");
+    }
 
     let mut nested_paths = Vec::new();
     let mut warnings = Vec::new();

tests/testsuite/workspaces.rs

@@ -2198,6 +2198,7 @@ fn ws_err_unused() {
         "[features]",
         "[target]",
         "[badges]",
+        "[lints]",
     ] {
         let p = project()
             .file(