Docs typos

[roman-wb]

Hi!

I found some typos in docs.

1. https://clickhouse.uptrace.dev/guide/clickhouse-queries.html#scan-and-exec
   Now for example "Scan columns into separate slices.":
   err := db.NewSelect().Model(&user).Column("id", "name").Limit(100).Scan(ctx, &ids, &names)
   Need:
   err := db.NewSelect().Model(&user).Column("id", "name").Limit(100).ScanColumns(ctx, &ids, &names)

2. https://clickhouse.uptrace.dev/guide/clickhouse-drop-table.html#api
   Now for example: IfNotExists().
   Need: IfExists()