docs: reformat by guide of Chinese writing style. (#10445)

1. added space between Chinese character and half-width character.
2. capitalized first letter of proper noun.
3. fixed node to Node.js.
4. corrected spell of vnode to VNode.
5. fixed typo of UINON to Union.
6. UNION & JOIN is not SQL clause here, so should be Union & Join.
7. avg, min, diff is SQL function here, so should be AVG, MIN, DIFF.
8. EMQ X should be EMQX.
9. replaced half-width parenthesis with full-width parenthesis.
10. translated split-brain
11. corrected collectd_statsd to collectd/StatsD