Antoine Stevan 9ebb61fc2d
FIX: correct bad span in std help errors (#9039)
# Description
##  before this PR
```
>_ std help modules euwioq
Error: nu:🐚:external_command

  × External command failed
     ╭─[help:259:1]
 259 │         if ($found_module | is-empty) {
 260 │             module_not_found_error (metadata $module | get span)
     ·                                    ──────────────┬──────────────
     ·                                                  ╰── Cannot convert record<start: int, end: int> to a string
 261 │         }
     ╰────
  help: All arguments to an external command need to be string-compatible
```
```
>_ std help externs euwioq
Error:
  × std::help::extern_not_found
     ╭─[help:401:1]
 401 │
 402 │     let extern = ($extern | str join " ")
     ·     ─┬─
     ·      ╰── extern not found
 403 │
     ╰────
```
> **Note**
> same kind of error with all the others

## ✔️ after this PR
```
> std help modules euwioq                                                                                         04/28/2023 05:45:50 PM
Error:
  × std::help::module_not_found
   ╭─[entry #2:1:1]
 1 │ std help modules euwioq
   ·                  ───┬──
   ·                     ╰── module not found
   ╰────
```
```
> std help externs euwioq                                                                                         04/28/2023 05:45:53 PM
Error:
  × std::help::extern_not_found
   ╭─[entry #3:1:1]
 1 │ std help externs euwioq
   ·                  ───┬──
   ·                     ╰── extern not found
   ╰────
```
> **Note**
> same with the others

# User-Facing Changes
fixes the errors to have proper messages

# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
-  `toolkit test`
-  `toolkit test stdlib`

# After Submitting
```
$nothing
```
2023-05-12 19:44:39 +02:00
..
2023-05-10 19:18:42 +02:00