Fix inconsistencies in InternalDocs/parser.md

[YangSiJun528]

typr in the memoization example appears to be a typo, since return_type is used elsewhere in this document for the same placeholder.

[python-cla-bot]

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[picnixz]

I do not think it is a typo though and I cknsider this not enough for just a typo change. However if you can find more typos in this document itself (or inconsistencies) we could make the contribution more valuable.

[ZeroIntensity]

What do you mean that this isn't a typo? This looks legitimate to me.

I think we should let this one through, as this is a first-time contributor. People often need some momentum to get started contributing, and typo fixes are a good way to get that first kick. (If it were someone scouring through CPython sending a PR for every little typo they see, then that would be different and I agree that we shouldn't encourage that, but this seems normal in nature.)

[YangSiJun528]

Thank you both for the feedback. I believe typr is a typo because every other generic rule_name[...] example I found in this document uses return_type.

Following the suggestion, I reviewed the rest of the document and fixed two additional issues: an incorrect Markdown link and an extra colon.

[picnixz]

What do you mean that this isn't a typo? This looks legitimate to me.

It is just a formal name so I would usually prefer that when fixing a typo in a document, the document in its entirety is reviewed. When there is a +/-1 change I never know whether this is the only change to do. But now we have a more complete contribution so thanks!