addon-docs show code block bleeds CSS classes

[MrHus]

Describe the bug
The addon-docs uses a CSS class called tag which collides with CSS classes used in the
style from the library it is documenting.

To Reproduce
Steps to reproduce the behavior:

1. Go to https://42bv.github.io/ui/storybook/?path=/docs/core-asynccontent--when-loaded
2. Click on show code
3. Notice the blue background on tags, and the missing text

Expected behavior
I expect to see a code block which can be read by the user.

Screenshots

System:
Environment Info:

System:
OS: macOS Mojave 10.14.6
CPU: (16) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
Binaries:
Node: 10.16.3 - ~/.nvm/versions/node/v10.16.3/bin/node
Yarn: 1.19.1 - ~/.nvm/versions/node/v10.16.3/bin/yarn
npm: 6.9.0 - ~/.nvm/versions/node/v10.16.3/bin/npm
Browsers:
Chrome: 78.0.3904.97
Firefox: 70.0
Safari: 13.0.3
npmPackages:
@storybook/addon-actions: 5.2.5 => 5.2.5
@storybook/addon-docs: 5.2.5 => 5.2.5
@storybook/preset-scss: 1.0.2 => 1.0.2
@storybook/preset-typescript: 1.1.0 => 1.1.0
@storybook/react: 5.2.5 => 5.2.5

[stale]

Hi everyone! Seems like there hasn't been much going on in this issue lately. If there are still questions, comments, or bugs, please feel free to continue the discussion. Unfortunately, we don't have time to get to every issue. We are always open to contributions so please send us a pull request if you would like to help. Inactive issues will be closed after 30 days. Thanks!

[shilman]

Closing this as dupe to #9414 which has more detail