Fix typos in pooling docs

Fix typos in pooling docs

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### Description
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- fixed typo in pooling doc that mentioned three items but had a list of 4
- fixed typo "whish" to "wish" in pooling doc

### Checklist
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This pull request is:

- [x] A documentation / typographical / small typing error fix
	- Good to go, no issue or tests are needed
- [ ] A short code fix
	- please include the issue number, and create an issue if none exists, which
	  must include a complete example of the issue.  one line code fixes without an
	  issue and demonstration will not be accepted.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.   one line code fixes without tests will not be accepted.
- [ ] A new feature implementation
	- please include the issue number, and create an issue if none exists, which must
	  include a complete example of how the feature would look.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.

**Have a nice day!**

Closes: #10411
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/10411
Pull-request-sha: 652ead00466ce2e85bdc2a62f7c69c16da6bb4fc

Change-Id: Ia5f2c5abfb0d76b5222aa883473291bba6df6de0