Better error handling using do (#5890)

* adds `capture-errors` flag for `do`

* adds `get-type` core command to get type

* fmt

* add tests in example

* fmt

* fix tests

* manually revert previous changes related to `get-type`

* adds method to check for error name using `into string`

* fix clippy

crates/nu-command/tests/commands/mod.rs

@@ -9,6 +9,7 @@ mod cp;
 mod date;
 mod def;
 mod default;
+mod do_;
 mod drop;
 mod each;
 mod echo;