builds.sr.ht/compatibility: add freebsd/13.x
builds.sr.ht/compatibility: freebsd images are updated weekly

The docs were outdated here.
git.sr.ht: fix typos
Add link to video
git.sr.ht: reduce heading numbers
git.sr.ht: update git send-email note
git.sr.ht: add detailed send-email web instructions
Link to Drew's video game guide in license page
Explicitly mention crypto mining in the ToS

This has always been a one-way ticket to a ban, just making it clear.
Link GraphQL schemes

This patch adds links to the GraphQL schemes in the Git repositories to
the graphql.md pages for {git,meta,todo}.sr.ht.  The playground also
contains the schemes, but it is only available for logged-in users.
And the source file makes it easier to jump to specific locations, to
share links and to track changes.
Link to todo.sr.ht GraphQL API docs

todo.sr.ht has a GraphQL API and a page describing it, but neither the
index page nor the api page linked to it.  This patch updates both pages
to link to the GraphQL documentation, as is already the case for
graphql: Fix curl invocation

curl does not support separating long options and their values by an
equals sign (only by spaces), see curl(1):
graphql: Fix example queries

The example queries were missing the outer query { ... } element (or
just { ...  })
graphql: Add link to todo.sr.ht playground

There also is a GraphQL playground for todo.sr.ht that was not mentioned
in the documentaion.
graphql: Fix Authorization header field

The HTTP header used for the access token is called Authorization, not
Update dispatch docs
Fix "Github" capitalisation
Update example manifests for pages.sr.ht
Fix `to to` typo
builds: document environment for dispatch.sr.ht