CIP-0030 | Fix API headers for markdown portability

[rphair]

Recognised in #591 (comment) (cc @SmaugPool) and cleaned up here since running this code through Showdown in site builders causes text inside angle brackets beginning \< to be dropped unless quoted literally in Markdown (as code would be).

To avoid too many unnecessary changes, I've only applied this change to the API section and not the preceding error types or data types. Perhaps for functional & aesthetic considerations other reviewers might think these literals should also be quoted as code. 🤔 cc @rooooooooob

• NOTE data type cbor<T> suffers the same problem I've also quoted it as code.
• @Ryun1 @Crypto2099 @SebastienGllmt please look at the code segment in that section where I've also removed the quote back-slashes, which also truncate the code in Showdown and don't look right to me as code in the first place (?). If the back-slashes are necessary in the code, maybe we can find a portable way of putting them back in. 😵‍💫

What we're mainly trying to achieve is the correct appearance of this page on the Dev Portal (cc @katomm), which currently has sections of code in many of the API section headers truncated (cc @KtorZ): https://developers.cardano.org/docs/governance/cardano-improvement-proposals/CIP-0030

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(how it renders with the changes in this branch)

[Ryun1]

I'm happy to remove the \s, I did this for my endpoints in CIP-95 already -- to me it just looks a little cleaner overall. We can make this the "standard" for web-bridges if we want.

This change also does not seem to affect existing links to sections which is super nice.

[rooooooooob]

LGTM. It would be nice if we could make them bigger while being code, but judging from CIP-95 it looks good still. And consistent with other CIP(s?) that had this issue. The API is pretty unhelpful as-is on the cardano site so you need to reference the github code, but when searching it's the cardano site that pops up and not the github one so this should help a lot.

[Crypto2099]

These changes look good to me and make sense as a standard we can attempt/encourage to follow going forward for other CIPs requiring code examples.