Can't use expression register (=) on vsvim.

[mandip1213]

Describe the bug
In vim in insert mode, on entering <C-r>= it goes into command mode and we can ask it for calculating certain expression.
For eg: <C-r>=123+456 will insert 579.
But on VsVim, it goes into insert(visual) mode.

It doesn't work even in normal mode with "=123+456. Is there anybody with a workaround? Thanks in advance.

To Reproduce
In insert mode: press <C-r>=
In normal mode: press "=12+34

Expected behavior
It should emulate the behaviour of expression register .)in vim.

Screenshots

Environment (please complete the following information):

• Visual Studio version: VS 2022 17.1.2
• VsVim version: 2.10.0.5
• Programming Language: cpp
• Check(Type 'x') any that are installed:
  • ReSharper
  • Visual Assist

Additional context
<C-r> is configured to handle with vsvim.

Note:
The following is written about contributing.
https://github.com/VsVim/VsVim/blob/master/CONTRIBUTING.md

General Keyboard configuration problems are described below.
#2527