Restructure find_path into a separate functions for modules and non-module items

Also renames `prefer_core` imports config to `prefer_no_std` and changes the behavior of no_std path searching by preferring `core` paths `over` alloc

crates/ide-completion/src/lib.rs

@@ -238,7 +238,7 @@ pub fn resolve_completion_edits(
                     db,
                     candidate,
                     config.insert_use.prefix_kind,
-                    config.prefer_core,
+                    config.prefer_no_std,
                 )
             })
             .find(|mod_path| mod_path.to_string() == full_import_path);