Fix some typos in Editors.md.

7 jobs for master in 10 minutes and 51 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #21009
fp
build-coq.8.7.1

00:05:07

passed #21008
fp
build-coq.8.7.2

00:05:02

passed #21007
fp-timing
build-coq.8.8.0

00:04:53

passed #21006
fp
build-coq.8.8.1

00:05:34

passed #21005
fp
build-coq.8.8.2

00:05:39

passed #21004
fp-timing
build-coq.8.9.dev

00:05:50

passed #21003
fp
build-coq.dev

00:08:06