Add documentation about how to use the `/servicenow search` command (and make hint for usage)

[brittanynavin]

I am unable to understand how to use the /servicenow search slash command after reading through your documentation. There are no usage examples in the documentation and no hint is displayed in Mattermost when you type /servicenow search.

[Kshitij-Katiyar]

@brittanynavin Just run the '/servicenow share' command without any parameters and it will open a modal containing 2 fields 1) Record Type: Here you can select the type of record you want to search 2) Search Box: Here you have to type at least 3 letters to search your record.

Please let me know if this helps or need anything else.