JSON flag not being accepted as resultformat for code coverage

[randi274]

Summary

Running this command featured in our documentation results in an error:
sfdx force:apex:test:run -n "MyTestName" -c --json

Steps To Reproduce:

1. Run this command: sfdx force:apex:test:run -n "MyTestName" -c --json, where MyTestName is the name of a valid test class.
2. Get this error: Select a result format when specifying code coverage

Expected result

--json is enough information for the code coverage result format.

Actual result

I need to add the resultformat to get it to work: sfdx force:apex:test:run -n "MyTestName" -c --resultformat=json

Additional information

We should either allow the --json flag to work without the --resultformat=json, or remove that example.

Apex library Version:
0.7.0