Apply StringFormatMethod on ILog Format methods

Hi, it would be nice to have Jetbrains’ StringFormatMethodAttribute or MessageTemplateFormatMethodAttribute applied on to all *Format signatures of ILog, so that Resharper\Rider users could easily see formatted parameters. Loggers like NLog are already doing this.

As stated in the official article, it’s not even necessary to reference the nuget package, since you could copy the implementation directly.

Added in this commit, that’s available from v5.5.1 that’s now available on MyGet.