Add Council as approver to all Standards Track XEPs where it was missing

[moparisthebest]

# find all missing approvers
comm -12 <(grep -Lo '<approver>.*</approver>' xep-0* | sort -u) <(ls xep-0* | sort -u) > xepsmissing_approver.txt
# inspect types
cat xepsmissing_approver.txt | xargs grep -ho '<type>.*</type>' | sort -u > xepsmissing_uniquetypes.txt
# add council as approver to all with type Standards Track
cat xepsmissing_approver.txt | xargs grep -lo '<type>Standards Track</type>' | xargs sed -ri 's@^(.*)<sig>(.+)</sig>@\1<sig>\2</sig>\n\1<approver>Council</approver>@'

For clarification I think this should be considered a "tooling change" and no versions or anything bumped, this triggered it: https://github.com/xsf/xeps/pull/1255#discussion_r1082096252

[tmolitor-stud-tu]

@Kev I think after merging #1255, this should be merged, too, no?

[Kev]

This doesn't pass CI at the moment.

[iNPUTmice]

Council has approved this PR and asked if we could do this without a version bump. Council considers this just a bug in the meta data / an editorial change