Description of the Issue

Languages which used to have their functions appear in the Function List have gone missing, or at least Rust no longer has support for navigating to functions via Function List

Steps to Reproduce the Issue

1. Open up or create a file with .rs extension
2. Make sure that a correctly defined function is in the file
3. Save the file
4. Observe that the function does not show up on the Function List

Debug Information

Notepad++ v7.9.5 (64-bit)
Build time : Mar 21 2021 - 02:13:17
Path : C:\Program Files\Notepad++\notepad++.exe
Admin mode : OFF
Local Conf mode : OFF
OS Name : Windows 10 Home (64-bit)
OS Version : 1909
OS Build : 18363.1440
Current ANSI codepage : 1252
Plugins : mimeTools.dll nppAutoDetectIndent.dll NppConverter.dll NppExport.dll NppMarkdownPanel.dll NppTextViz.dll

Other info

I am certain that Rust used to be supported. A Rust file I've been working on no longer has its function's appear. I believe that the version I was using before was 7.9.1.