update #credentialcreationoptions-extension & #credentialrequestoptions-extension section titles

[equalsJeffH]

update #credentialcreationoptions-extension & #credentialrequestoptions-extension section titles such that they are not confused with (webauthn) "extensions". e.g.:

CredentialCreationOptions Dictionary Extension ### {#credentialcreationoptions-extension}

CredentialRequestOptions Dictionary Extension ### {#credentialrequestoptions-extension}

[AngeloKai]

I get the interest in furthering clarifying this. Perhaps an easy fix is to get the word 'extension" from the section titles?

[equalsJeffH]

i would rather just add "Dictionary" to the titles as illustrated above.

[equalsJeffH]

might as well fix this for CR. PR #734 is now open.