Allow primary key comment on create table statement

[guigs]

This PR adds support for primary key column comment with primary_key_comment option to create_table.

Before this schema dump/load was not able to keep a comment that was added to a primary key column.

This PR complements #36384.

[kamipo]

I'm not prefer to add new column option for primary key on create_table.
If we already be able to create a pk column with comment (e.g. t.primary_key :id, comment: "Primary key comment"), it could be implemented to dump the schema without new option.

[guigs]

Yea, I was not very happy to add a new option either. Do you suggest that whenever the pk column has a comment, we should add explicit primary key statement t.primary_key in schema? I can investigate that possibility.

[rails-bot]

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