Clarify when authorization and rate-limiting are not applicable

Fixes https://github.com/matrix-org/matrix-doc/issues/1971

changelogs/client_server/newsfragments/2090.clarification

@@ -0,0 +1 @@
+Clarify when authorization and rate-limiting are not applicable.

scripts/templating/matrix_templates/templates/http-api.tmpl

@@ -10,8 +10,8 @@
 
 {{endpoint.desc}}
 
-{{":Rate-limited: Yes." if endpoint.rate_limited else "" }}
-{{":Requires auth: Yes." if endpoint.requires_auth else "" }}
+{{":Rate-limited: Yes." if endpoint.rate_limited else ":Rate-limited: No." }}
+{{":Requires auth: Yes." if endpoint.requires_auth else ":Requires auth: No." }}
 
 .. class:: httpheaders