IME with input hint along with the cursor can't input

**Steps to reproduce:**

1. use QQ shuangpin IME or IME with input hint along  like this: input 't', IME shows 't|[ta]', '|' simulates the cursor position

**Expected behaviour:**
input normally

**Observed behaviour:**
can't input 

**Workaround:**
fix the `applyChangeToValue` inner `insert` and `spliceEnd` logic
