Motivation / Problem

Just after hitting merge, I was like: this felt wrong ..

Feel free to close this PR if this is overly pedantic of me.

Description

It didn't sit well to me, how I wrote the commit initially. First
casting a variable into another, only to write it back into the
originally feels wrong.

This flow makes a bit more sense to me.

Limitations

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, gs_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • newgrf_debug_data.h may need updating.
  • PR must be added to API tracker