Change: 'string' is spurious in 'Filter string:'

[andythenorth]

Motivation / Problem

• Word 'string' is spurious in 'Filter string:' labels for filter UI widgets
• Also related tooltips wording can be improved

People who are not programmers or linguists or mathematicians do not commonly know what 'string' is.
It's 2022, filter widgets are an established pattern in the world.

Description

• Removed 'string' from labels for filter UI widgets
• Also update related tooltips

Limitations

Describe here

• Is the problem solved in all scenarios?

As far as I can find by searching src/lang/english.txt and clicking around the UI.

• Is this feature complete? Are there things that could be added in the future?

No other translations have been touched.

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 touches english.txt or translations? Check the guidelines
• 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

[andythenorth]

Can add screenshots if that is needed. Not sure it is 😛

[andythenorth]