Spelling (#4101)

* spelling: action

* spelling: artifacts

* spelling: asymmetric

* spelling: attempts

* spelling: bizarre

* spelling: certbot

* spelling: certificate

* spelling: certainly

* spelling: challenge

* spelling: client

* spelling: collated

* spelling: correct

* spelling: considered

* spelling: custom

* spelling: distinguish

* spelling: encoding

* spelling: enhancement

* spelling: equivalent

* spelling: execution

* spelling: existence

* spelling: failed

* spelling: handshake

* spelling: hyphen

* spelling: initialized

* spelling: initialization

* spelling: interpretation

* spelling: letsencrypt

* spelling: multiline

* spelling: multipart

* spelling: necessary

* spelling: otherwise

* spelling: output

* spelling: overridden

* spelling: positives

* spelling: preferable

* spelling: progress

* spelling: recommended

* spelling: referring

* spelling: relativity

* spelling: request

* spelling: requiring

* spelling: separate

* spelling: source

* spelling: specified

* spelling: standard

* spelling: successfully

* spelling: unparseable

* spelling: useful

certbot/achallenges.py

@@ -1,6 +1,6 @@
 """Client annotated ACME challenges.
 
-Please use names such as ``achall`` to distiguish from variables "of type"
+Please use names such as ``achall`` to distinguish from variables "of type"
 :class:`acme.challenges.Challenge` (denoted by ``chall``)
 and :class:`.ChallengeBody` (denoted by ``challb``)::