Fix character creation command casing

[saikatdas0790]

Corrected the casing of 'Fighter' to 'fighter' in the command example.

Description of Changes

Fixed the casing otherwise the command would not work and show this error:

ERROR: create_character: External attempt to call reducer "create_character" failed, invalid arguments.
This is likely due to a mismatched client schema, have you run `spacetime generate` recently?

Expected complexity level and risk

1

Testing

Tested locally

[CLAassistant]

All committers have signed the CLA.