Markdown shown in search previews

[imaustink]

See __testing__ bellow the ATM Guide result.

Justin suggests fixing this similar to how it's handled for title attributes.

[mickmcgrath13]

https://github.com/bit-docs/bit-docs-generate-searchmap/blob/master/generators/search-map.js#L31

[imaustink]

Solved by bit-docs/bit-docs-generate-searchmap#4