[Atlas Search] Highlighting in the Syntax block on Synonyms page in Atlas search is wrong

When I look at Syntax for synonyms, the several of the lines are not highlighted and some of irrelevant lines are highlighted. 

Looks like a regression after StoredSource was added to the index definition:

https://www.mongodb.com/docs/atlas/atlas-search/synonyms/#syntax

CC kanchana.sekhar@mongodb.com