📝 Add docstrings to feat/pgsql-driver

Docstrings generation was requested by @scottmckendry.

* https://github.com/tinyauthapp/tinyauth/pull/892#issuecomment-4524261246

The following files were modified:

* `internal/repository/postgres/db.go`
* `internal/repository/postgres/store.go`

internal/repository/postgres/db.go

@@ -16,6 +16,8 @@ type DBTX interface {
 	QueryRowContext(context.Context, string, ...interface{}) *sql.Row
 }
 
+// New returns a *Queries configured to use the provided DBTX for executing database operations.
+// The returned *Queries will use db as its database handle for all query method calls.
 func New(db DBTX) *Queries {
 	return &Queries{db: db}
 }