fix: syntax highlight broken on function calls or return value

[marxus]

fix:

• function keyword not being highlighted as a keyword
• objects passed as a function arguments had broken highlight

changes:

• removed special "treatment" for jsonnet "builtin" functions (std.*)[1]

[1] those functions are not part of the language nor keywords, they are stdlib... usually there is no stdlib highlights on other langs

hopefully the screenshots are clear enough

Broken 1:

Fixed 1:

Broken 2:

Fixed 2:

[CLAassistant]

All committers have signed the CLA.

[marxus]

thanks for merging. can it be published/released as 0.6.2?