[Bug] Some characters do not surround but delete text instead

Highlighting text and then typing the backtick character `` ` `` does not work and replaces the selected text with a single `` ` ``. However, all other characters available by default (`'"<([{` and matching closing characters) work just fine.

Additional characters defined in `SurroundSelection.ini` (placed in the same folder as the `.dll` file) do not work either.

My version info:

```
Notepad++ v8.4.6 (32-bit)
Build time : Sep 25 2022 - 19:55:26
Path : C:\Program Files (x86)\Notepad++\notepad++.exe
Command Line :
Admin mode : OFF
Local Conf mode : OFF
Cloud Config : OFF
OS Name : Windows 10 Enterprise (64-bit)
OS Version : 21H2
OS Build : 19044.2130
Current ANSI codepage : 1252
Plugins :
SurroundSelection (1.4.1)
```

This occurs for different language modes (I tried plaintext, markdown and python) and encodings (I tried UTF8 and ANSI). I use an English KB layout.

Please let me know if I can provide you with additional information.

Start by reproducing the issue in Notepad++ with the backtick and with additional characters from SurroundSelection.ini, using the reported plugin version and configurations. Trace the plugin's selection-surrounding and character/configuration handling; done means backticks and configured characters surround selected text instead of replacing it.

Written by the indexing model from the issue text.