docs: fix MDX parse error in query/quickstart

[alan707]

Problem

docs/query/quickstart.mdx fails to parse with Mintlify (and standard MDX parsers) due to multi-line <p> elements inside <Accordion> JSX components:

Expected a closing tag for `<p>` before the end of `paragraph`

In MDX, a <p> tag whose content wraps to the next line is treated as ending at the first line break, before the closing </p> tag is seen.

Fix

Remove the <p> wrapper elements from the three <Accordion> blocks. MDX handles paragraph formatting automatically inside JSX components.