[web] set Vary response header to "Accept-Language" when using content negotiation This is slightly annoying because the response actually only varies based on the language we decide to send, which has much fewer possible values than Accept-Language, but that's not in the request, so we can't easily use it. Deployments using varnish or similar and controlling the set of available languages will likely want to override this to allow reasonable amounts of caching. Closes #2105812

[MESSAGES CONTROL]
disable-msg = C0301

[VARIABLES]
# Enable / disable this checker
enable-variables = yes
additional-builtins = _, display_name

[BASIC]
required-attributes=
attr-rgx = (w|[a-z_][a-z0-9_]{2,30})
variable-rgx = (w|[a-z_][a-z0-9_]{2,30})$
argument-rgx = (w|[a-z_][a-z0-9_]{2,30})$

[TYPECHECK]
generated-members=debug,info,notice,warning,error,critical,exception