Add proposal to make reason option on content reporting

proposals/0000-optional-content-reporting-reason.md

@@ -0,0 +1,13 @@
+# MSC0000: Make `reason` optional for reporting content
+
+Currently, the spec says that the `reason` parameter on the content reporting
+endpoint is required, but also says that the string "may be blank." This
+seems to be a contradiction.
+
+This MSC proposes that the `required` flag for this parameter be removed, as
+well as the "may be blank" clause in the description.
+
+Note that the kicking and banning endpoints already have optional `reason`
+parameters. The other endpoints mentioned in #2367 will likely also add
+optional `reason` parameters, so it seems that it would be more more consistent
+with the rest of the spec to make this optional as well.