Autocompleted command suggestions don't replace arguments fully, leaving its characters after cursor unchanged

When using command suggestions, argument is not replaced fully, leaving its characters after the cursor unchanged, causing command syntax errors

Steps to reproduce:

1. Open chat and type in any command
2. Set the cursor position to be at the start of the command
3. Select any command from command suggestions list
4. Notice that function name characters after cursor remain unchanged, causing syntax errors

Expected result:

When using command suggestions, argument should be replaced fully

Observed result:

When using command suggestions, argument characters are not deleted fully, leaving its characters after the cursor unchanged, causing command syntax errors.