Fix doc replicated words

[smiletrl]

• One small doc fix
• Pgx pool QueryRow misses release https://github.com/jackc/pgx/blob/master/pgxpool/pool.go#L456

[jackc]

The connection can't be released until the row is scanned and the release happens when it is scanned. See #1050 for more discussion of the same issue.

[smiletrl]

ah, I see. Could you help describe the race condition if release happens before scan? or how to reproduce the race issue.

[smiletrl]

Right now, QueryRow must be chained by Scan(), otherwise it will eat all available connections. In this case, I feel QueryRow should be removed, but replaced with something like QueryRowScan, which will always release the connection.

Is this struct Pool implementing some interface, which must include QueryRow?

[jackc]

Why would QueryRow be called without also calling Scan?

[smiletrl]

ah, personally I don't have a specific case without calling Scan. Just feel it doesn't look right that if one function must be chained by another one, otherwise it could break the application, like bug reported at #1050.

[smiletrl]

This release is removed now^ This pr only fixes that doc.