Add more input/output type annotations (#7532)

crates/nu-command/src/database/commands/into_sqlite.rs

@@ -20,6 +20,9 @@ impl Command for IntoSqliteDb {
 
     fn signature(&self) -> Signature {
         Signature::build("into sqlite")
+            .input_output_types(vec![(Type::Any, Type::Nothing)])
+            .allow_variants_without_examples(true)
+            // TODO: narrow disallowed types
             .required(
                 "file_name",
                 SyntaxShape::String,

crates/nu-command/src/database/commands/query_db.rs

@@ -18,6 +18,7 @@ impl Command for QueryDb {
 
     fn signature(&self) -> Signature {
         Signature::build(self.name())
+            .input_output_types(vec![(Type::Any, Type::Any)])
             .required(
                 "SQL",
                 SyntaxShape::String,

crates/nu-command/src/database/commands/schema.rs

@@ -16,6 +16,7 @@ impl Command for SchemaDb {
 
     fn signature(&self) -> Signature {
         Signature::build(self.name())
+            .input_output_types(vec![(Type::Any, Type::Any)])
             .input_type(Type::Any)
             .output_type(Type::Any)
             .category(Category::Custom("database".into()))