*: update the HTTP API about "upgrade" and fix a minor doc issue

[zimulala]

What problem does this PR solve?

Issue Number: close #46424

Problem Summary:

• Update /upgrade?op={op} to /upgrade/{op} and add related doc
• Fix a minor doc issue
  Before this PR:

After this PR:

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[tiprow]

Hi @zimulala. Thanks for your PR.

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[Defined2014]

Don't forget update user doc.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Defined2014, hawkingrei

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• OWNERS [Defined2014,hawkingrei]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-08-25 08:43:53.621883079 +0000 UTC m=+1484598.170899051: ☑️ agreed by Defined2014.
• 2023-08-25 08:57:41.098210066 +0000 UTC m=+1485425.647226050: ☑️ agreed by hawkingrei.

[codecov]

Codecov Report

Merging #46425 (a245c3a) into master (2adb1dc) will decrease coverage by 0.6814%.
Report is 4 commits behind head on master.
The diff coverage is 100.0000%.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #46425        +/-   ##
================================================
- Coverage   73.3923%   72.7110%   -0.6814%     
================================================
  Files          1295       1316        +21     
  Lines        393620     399843      +6223     
================================================
+ Hits         288887     290730      +1843     
- Misses        86361      90669      +4308     
- Partials      18372      18444        +72     

Flag	Coverage Δ
integration	25.6256% <14.2857%> (?)
unit	73.3939% <100.0000%> (+0.0015%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	54.0444% <ø> (ø)
parser	85.0633% <ø> (ø)
br	47.9817% <ø> (-4.3490%)	⬇️