Recognise URLs in plain text message bodies (#476)

src/message/html.rs

@@ -524,11 +524,11 @@ impl StyleTree {
 }
 
 pub struct TreeGenState {
-    link_num: u8,
+    pub link_num: u8,
 }
 
 impl TreeGenState {
-    fn next_link_char(&mut self) -> Option<char> {
+    pub fn next_link_char(&mut self) -> Option<char> {
         let num = self.link_num;
 
         if num < 62 {

src/message/mod.rs

@@ -72,6 +72,7 @@ mod state;
 
 pub use self::compose::text_to_message;
 use self::state::{body_cow_state, html_state};
+pub use html::TreeGenState;
 
 type ProtocolPreview<'a> = (&'a Protocol, u16, u16);