[BUG] "Invalid variable name" after turning on psutil

**To Reproduce**

- I turn on the use of psutil
- I presume that having Discord open (with a title that uses fancy characters/emojis) could have something to do with that.
- I search for discord using 'di'
- *Crash*

**Info (please complete the following information):**
- Bashtop version: 0.9.25
- (Linux) Linux distribution and version: Manjaro on 6.6.54-2
- (Linux) Data collection type (/proc or psutil): psutil
- Psutil version: `python3 -c "import psutil; print(psutil.version_info)"` (version 5.7.0 or above is required): 6.0.0
- Terminal used: Kitty
- Font used: Some nerdfont
- Bash version, `bash --version` (version 4.4 or above is required): 5.2.37
- Locales: output of `locale -v`
```
LANG=en_US.utf8
LC_CTYPE="en_US.utf8"
LC_NUMERIC=nl_BE.UTF-8
LC_TIME=nl_BE.UTF-8
LC_COLLATE="en_US.utf8"
LC_MONETARY=nl_BE.UTF-8
LC_MESSAGES="en_US.utf8"
LC_PAPER=nl_BE.UTF-8
LC_NAME=nl_BE.UTF-8
LC_ADDRESS=nl_BE.UTF-8
LC_TELEPHONE=nl_BE.UTF-8
LC_MEASUREMENT=nl_BE.UTF-8
LC_IDENTIFICATION=nl_BE.UTF-8
LC_ALL=
```

**Additional context**

contents of `$HOME/.config/bashtop/error.log`

```
New instance of bashtop version: 0.9.25 Pid: 80351
/usr/bin/bashtop: line 3405: pid_├─_graph: invalid variable name

New instance of bashtop version: 0.9.25 Pid: 86220
/usr/bin/bashtop: line 3405: pid_Pid:▼Program:_graph: invalid variable name

New instance of bashtop version: 0.9.25 Pid: 86426
/usr/bin/bashtop: line 3405: pid_Pid:▼Program:_graph: invalid variable name

New instance of bashtop version: 0.9.25 Pid: 86586
/usr/bin/bashtop: line 3405: pid_Pid:▼Program:_graph: invalid variable name

New instance of bashtop version: 0.9.25 Pid: 86843
/usr/bin/bashtop: line 3405: pid_Pid:▼Program:_graph: invalid variable name

New instance of bashtop version: 0.9.25 Pid: 87144
/usr/bin/bashtop: line 3405: pid_Pid:▼Program:_graph: invalid variable name

New instance of bashtop version: 0.9.25 Pid: 87635
/usr/bin/bashtop: line 3405: pid_Pid:▼Program:_graph: invalid variable name

New instance of bashtop version: 0.9.25 Pid: 88578

New instance of bashtop version: 0.9.25 Pid: 88771
```