Add a todo in readme

gemmarx · gemmarx · commit 45e13d53b7c0 · 2016-08-01T12:25:15.000+09:00
diff --git a/readme.md b/readme.md
@@ -95,6 +95,7 @@ convert Half-width-kana into normal Katakana with diacritical marks combined  [
 combine base characters and diacritical marks on Hiragana/Katakana [かﾞハ゜ -> がパ]
 
 ## TODO or NOT TODO
+- Voiced-sound-marks -> no space combining style "\u{3099}"
 - Half-width-kana <- normal Katakana
 - (normal/wide)tilde <-> Wave-dash
 
