toml_edit tables: clippy.toml forbidden methods

I used this file and
   clippy -- -A clippy::all -D clippy::disallowed_methods
to find the places I needed to fix.

Author: ijackson

clippy.toml

@@ -0,0 +1,4 @@
+disallowed-methods = [
+    { path = "toml_edit::Item::as_table", reason = "Use .as_table_like instead!" },
+    { path = "toml_edit::Item::is_table", reason = "Use .is_table_like instead!" },
+]