fix(docs): angular docs code highlight theme

[owilliams320]

Description

Fix for the code highlight in docs using only the light theme

Test Steps

• [ ] npm run start
• [ ] then open the localhost:4200
• [ ] finally go to any code snippet and set system settings to use dark mode

General Tests for Every PR

• [ ] npm run start still works.
• [ ] npm run lint passes.
• [ ] npm run stylelint passes.
• [ ] npm test passes and code coverage is not lower.
• [ ] npm run build still works.

Screenshots or link to StackBlitz/Plunker

[owilliams320]

:tada: This PR is included in version 7.3.1 :tada:

The release is available on:

• v7.3.1
• GitHub release

Your semantic-release bot :package::rocket: