Change: Minor widget changes.

[PeterN]

Motivation / Problem

1. Default colour of widget text is blue (TC_FROMSTRING is the same value as TC_BLUE), but most windows use black text.
2. Redundant SetDataTip() which set the default values again.
3. Some windows have custom drawing code just to draw some text where the default widgets can handle this directly. This PR addresses a few of these.

Description

Resolved by...

1. Default widget text colour is changed to TC_BLACK, to avoid needing explicit SetTextColour() calls. Most strings start with a colour code so are unaffected.
2. SetDataTip removed where unnecessary.
3. Custom drawing replaced with appropriate widget parameters.

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 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