sketch out zz, plan other modes

src/main.rs

@@ -15,13 +15,18 @@ const CHUNKS_PER_LINE: usize = BYTES_PER_LINE / BYTES_PER_CHUNK;
 
 // TODO:
 // - modes
-//   - g/v/z
+//   - select
+//   - insert
+//   - zz/zt/zb
 // - search
 // - jumplist
 // - modifications
 //   - insert/append
+//     - mode
 //   - replace
+//     - partial action
 //   - replace-and-keep-going
+//     - mode
 //   - delete
 //   - change