[DOCS] Add new conf about kryo registrator to spark start command

[eric9204]

Change Logs

make the spark start command consistent with the README.md

Impact

none

Risk level (write none, low medium or high below)

none

Documentation Update

• The config description must be updated if new configs are added or the default value of the configs are changed
• Any new feature or user-facing change requires updating the Hudi website. Please create a Jira ticket, attach the
  ticket number here and follow the instruction to make
  changes to the website.

Contributor's checklist

• Read through contributor's guide
• Change Logs and Impact were stated clearly
• Adequate tests were added if applicable
• CI passed

[yihua]

Thanks @eric9204 for revising the Spark guide. Could you also update the docs of release 0.13.x under website/versioned_docs?

[eric9204]

Thanks @eric9204 for revising the Spark guide. Could you also update the docs of release 0.13.x under website/versioned_docs?

@yihua Has been updated！

[yihua]

LGTM