Expand Query named binds recognition

[paulbalandan]

Description
Another pass to fixing named binds recognition by adding a negative lookahead for := types.

Fixes #4760 .
Supersedes and closes #4764

Checklist:

• Securely signed commits
• Unit testing, with >80% coverage
• Conforms to style guide

[MGatner]

I don't feel qualified to assess the underlying issue and solution, but the code is fine.

[vlakoff]

The outer parentheses are useless, so the code could be slightly simplified to:

preg_match('/:(?!=).+:/', $sql)

[paulbalandan]

That's true, as we're not saving the matches. If you like, you can send a PR to simplify it.

[kenjis]

This fix is very difficult to understand. Because the bug is related to Query Builder.

When $builder->where('id', 1), Query Builder creates a query like WHERE "id" = :id: inside.

When $builder->where('LOWER(jobs.name)', 'accountant'),
it creates WHERE LOWER(jobs.name) = :LOWER(jobs.name):.

And after all Query::compileBinds() binds the value.

Query Builder uses Named Bindings.