Multiple string format conventions at play should be made uniform.

WCT has more than one way to format a string.

## SPDLOG style

```c++
log->debug("this is {} style", "spdlog");
```

## Boost style

```c++
std::string s = String::format("this is %s style", "boost");
```

## Fix

To fix this, I think we should wait for when C++20 becomes the minimum C++ standard version (we are still at 17).  At that point, we should only use `std::fmt`.

