docs(fundamentals): more polishing

[alexcg1]

• docs(fundamentals): polish document api
• docs(fundamentals): polish documentarray api
• docs(fundamentals): polish documentmemmaparray api

[github-actions]

This PR closes: #11a

[github-actions]

Latency summary

Current PR yields:

• 🐢🐢 index QPS at 1173, delta to last 2 avg.: -24%
• 🐢🐢 query QPS at 52, delta to last 2 avg.: -21%
• 🐢🐢 dam extend QPS at 32164, delta to last 2 avg.: -23%
• 🐢🐢 avg flow time within 1.4291 seconds, delta to last 2 avg.: +10%
• 🐎🐎🐎🐎 import jina within 0.5587 seconds, delta to last 2 avg.: +26%

Breakdown

Version	Index QPS	Query QPS	DAM Extend QPS	Avg Flow Time (s)	Import Time (s)
current	1173	52	32164	1.4291	0.5587
2.4.3	1726	73	44987	1.0693	0.4485
2.4.2	1385	59	39469	1.5263	0.4355

Backed by latency-tracking. Further commits will update this comment.