Update webview.py

[freemedom]

Description

https://github.com/glutanimate/highlight-search-results/issues/3

It only tested some simple cases on my windows computer, but not do any other tests.

Checklist:

Please replace the space inside the brackets with an x and fill out the ellipses if the following items apply:

• [x] I've read and understood the contribution guidelines
• [ ] I've tested my changes against at least one of the following Anki builds:
  • [ ] Latest standard Anki 2.1 binary build
  • [ ] Latest alternative Anki 2.1 binary build
• [ ] I've tested my changes on at least one of the following platforms:
  • [ ] Linux, version:
  • [ ] Windows, version:
  • [ ] macOS, version:
• [ ] My changes potentially affect non-desktop platforms, of which I've tested:
  • [ ] AnkiMobile, version:
  • [ ] AnkiDroid, version:
  • [ ] AnkiWeb

[freemedom]

i just added different colors.