fix the span of the global std help item

[amtoine]

related to

• FIX: have consistent errors between std help and std help ... #9101
• FIX: correct bad span in std help errors #9039

Description

i actually forgot to fix in #9039 the new "item" introduced by #9101... 👀
there it is 😇

User-facing changes

going from

> std help git-commiteuwqi
Help pages from external command git-commiteuwqi:
No manual entry for git-commiteuwqi
Error:
  × std::help::item_not_found
     ╭─[help:721:1]
 721 │
 722 │     let item = ($item | str join " ")
     ·     ─┬─
     ·      ╰── item not found
 723 │
     ╰────

to

> std help git-commiteuwqi
Help pages from external command git-commiteuwqi:
No manual entry for git-commiteuwqi
Error:
  × std::help::item_not_found
   ╭─[entry #2:1:1]
 1 │ std help git-commiteuwqi
   ·          ───────┬───────
   ·                 ╰── item not found
   ╰────

Tests + Formatting

• 🟢 toolkit fmt
• 🟢 toolkit clippy
• ⚫ toolkit test
• ⚫ toolkit test stdlib

After Submitting

$nothing

[codecov]

Codecov Report

Merging #9184 (b62fbdb) into main (9ebb61f) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #9184   +/-   ##
=======================================
  Coverage   68.99%   68.99%           
=======================================
  Files         641      641           
  Lines      102467   102467           
=======================================
  Hits        70692    70692           
  Misses      31775    31775           

see 2 files with indirect coverage changes