Improve error message for missing rf=n in sharded table creation

[PavelShilin89]

Bug Description:

When the CREATE TABLE command does not include the rf=n (replication factor) parameter, instead of the ERROR 1064 (42000): P03: syntax error, unexpected integer, expecting string near '3' a more informative error message should be returned, explaining that rf=n is required.

Suggested improved error message:

ERROR 1064 (42000): Sharded table requires `rf=n`

Manticore Search Version:

Latest dev version

Operating System Version:

Ubuntu Jammy

Have you tried the latest development version?

Yes

Internal Checklist:

^{To be completed by the assignee. Check off tasks that have been completed or are not applicable.}

• Implementation completed
• Tests developed
• Documentation updated
• Documentation reviewed
• Changelog updated

[donhardman]

Fix implemented in this pull: #426

[donhardman]

@Nick-S-2018 please review