Update similarity.asciidoc

[blueSky1825821]

DFRSimilarity -> DFR similarity

• Have you signed the contributor license agreement?
• Have you followed the contributor guidelines?
• If submitting code, have you built your formula locally prior to submission with gradle check?
• If submitting code, is your pull request against master? Unless there is a good reason otherwise, we prefer pull requests against master and will backport as needed.
• If submitting code, have you checked that your submission is for an OS and architecture that we support?
• If you are submitting this code for a class then read our policy for that.

[elasticmachine]

Pinging @elastic/es-search (:Search/Ranking)

[elasticmachine]

Pinging @elastic/es-docs (>docs)

[cbuescher]

Thanks for the correction @blueSky1825821, the change is good, but could you please sign the CLA so we can merge this?

[blueSky1825821]

Thanks for the correction @blueSky1825821, the change is good, but could you please sign the CLA so we can merge this?

I signed the CLA, please recheck it

[cbuescher]

@blueSky1825821 sorry, I cannot find the email you used in this commit in our recods. You might have signed the CLA with a different e-mail than the one used in yout Git commit. Can you add this e-mails into your Github profile (can be hidden), so we can match your e-mails to your Github profile for the CLA checker?

[cbuescher]

LGTM

[cbuescher]

Thanks for signing, looks good now.
I will run the tests.
@elasticmachine test this please

[cbuescher]

Thanks @blueSky1825821, merged to 7.5 and up.