Auto merge of #12961 - epage:dead, r=weihanglo

refactor(toml): Remove unused method

### What does this PR try to resolve?

While finding better homes for logic for #12801, I found this part of the workspace-inheritance trait was unused.

### How should we test and review this PR?

### Additional information

src/cargo/util/toml/mod.rs

@@ -1548,9 +1548,6 @@ pub trait WorkspaceInherit {
     /// This is the workspace table that is being inherited from.
     /// For example `[workspace.dependencies]` would be the table "dependencies"
     fn inherit_toml_table(&self) -> &str;
-
-    /// This is used to output the value of the implementors `workspace` field
-    fn workspace(&self) -> bool;
 }
 
 impl<T, W: WorkspaceInherit> schema::MaybeWorkspace<T, W> {
@@ -1598,10 +1595,6 @@ impl WorkspaceInherit for schema::TomlWorkspaceField {
     fn inherit_toml_table(&self) -> &str {
         "package"
     }
-
-    fn workspace(&self) -> bool {
-        self.workspace
-    }
 }
 
 impl schema::TomlWorkspaceDependency {
@@ -1684,10 +1677,6 @@ impl WorkspaceInherit for schema::TomlWorkspaceDependency {
     fn inherit_toml_table(&self) -> &str {
         "dependencies"
     }
-
-    fn workspace(&self) -> bool {
-        self.workspace
-    }
 }
 
 impl<P: ResolveToPath + Clone> schema::TomlDependency<P> {