#784 Improve error message handling

[Erik Hänel]

The information of error messages are mostly distributed over the whole error message and therefore hard to understand. Apply the following changes:

• If a line information is present, jump to the corresponding line in the editor (at least supply an option to do so). It might also be helpful to add the error message as inline annotation, which will disappear e.g. after saving).
• Change the structure of an error message into the following:
  1. Start with a summary
  2. Gather the necessary information for error location
  3. Add a explainatory description (Instead of creating new language identifiers, we'll use the line break for separation)
  4. Remove the script abortion part as the important information is already in 2.
• Reduce the amount of red styled text to reduce the optical noise. It might be enough to colour lines and headlines read and leave the remaining text in standard colour.

Analysis:

Should be implemented as described by the analysis. Will need some major changes in the error handling to actually gather the necessary position information. We won't change th colour as completely red is kind of a de-facto industry standard.

Implementation:

• Implementation: Implemented as proposed by description and analysis. We did not implement the error annotations as that might be better implemented using EOL annotations, which are not yet available in our version of Scintilla.
• Revision: [r1322]
• Implementation test: Different error messages were provoked and did show up as expected.

Documentation:

• [x] ChangesLog updated
• [x] Code changes commented
• Documentation articles:
  • [ ] corresponding documentation articles updated
  • [ ] new documentation articles created
  • [x] not needed
• Language files:
  • [x] corresponding language files updated
  • [ ] not needed

Tests:

This change was tested manually. No deviation detected.