Revert "Support Rust expression like {x.y} in SQL strings"

This reverts commit b86d9321b5.

rusqlite-macros/tests/test.rs

@@ -16,30 +16,7 @@ fn test_literal() -> Result {
     let first_name = "El";
     let last_name = "Barto";
     let mut stmt = Stmt;
-    __bind!(stmt "SELECT $first_name, {last_name}");
-    Ok(())
-}
-
-#[test]
-fn test_tuple() -> Result {
-    let names = ("El", "Barto");
-    let mut stmt = Stmt;
-    __bind!(stmt "SELECT {names.0}, {names.1}");
-    Ok(())
-}
-
-#[test]
-fn test_struct() -> Result {
-    struct Person<'s> {
-        first_name: &'s str,
-        last_name: &'s str,
-    }
-    let p = Person {
-        first_name: "El",
-        last_name: "Barto",
-    };
-    let mut stmt = Stmt;
-    __bind!(stmt "SELECT {p.first_name}, {p.last_name}");
+    __bind!(stmt "SELECT $first_name, $last_name");
     Ok(())
 }