Support URL: https://inbuxa.org in the IMAP ID response and README

crates/imap/src/op/capability.rs

@@ -72,6 +72,8 @@ impl<T: SessionStream> Session<T> {
                         types::brand!(),
                         "\" \"version\" \"1.0.0\" \"vendor\" \"",
                         types::brand!(),
+                        "\" \"support-url\" \"",
+                        types::brand_url!(),
                         "\")\r\n"
                     )
                     .as_bytes()

crates/types/src/branding.rs

@@ -37,3 +37,11 @@ macro_rules! brand_prodid {
         concat!("-//", $crate::brand!(), "//", $crate::brand_server!(), "//EN")
     };
 }
+
+/// The project's website, given to clients as the support URL (IMAP `ID`).
+#[macro_export]
+macro_rules! brand_url {
+    () => {
+        "https://inbuxa.org"
+    };
+}