Amend PDO driver-specific class names

[kocsismate]

As suggested in https://externals.io/message/123166

[SakiTakamachi]

If Tim's RFC is passed, the PDO class could become the Pdo class.
https://wiki.php.net/rfc/class-naming-acronyms

In that case the stub would look like this:

class Dblib extends PDO

to

class Dblib extends Pdo

This may not happen due to backward compatibility issues, but I'd like to comment as a memorandum.

[kocsismate]

Was there any conclusion in the thread? It would be nice if we could implement these changes.

[SakiTakamachi]

I haven't received a response so I'll try emailing again.

[SakiTakamachi]

@kocsismate

It's been a week since I sent the email, and so far there have been no objections.

In my opinion, it's ok to merge this, but should we wait a bit longer?

[devnexen]

pdo_pgsql looks good

[TimWolla]

@kocsismate You'll also need to adjust the names in NEWS/UPGRADING.

[kocsismate]

@TimWolla Yeah, I know I forgot, but it's going to be fixed soon: #14299 (comment)