Create RStudio addin for %<-%

[dkahle]

Simple adding for %<-%. I think I crossed all t's and dotted all i's, but let me know if I've missed something!

[nteetor]

Hello @dkahle, thank you for the pull request. Could you provide a little more context and detail about your PR?

[dkahle]

Sure @nteetor. RStudio has native modifiable hotkeys for the assignment operator <- and the pipe %>% (see Tools > Modify Keyboard Shortcuts...), but there is no similar hotkey for %<-%. This commit allows for the addition of one in the sense that, after installing the update (and maybe reopening RStudio), there will be an option in that modify keyboards shortcut menu allowing users to map %<-% to a hotkey sequence. Does that help? It shouldn't change any behavior of in the package other than making it mappable, but not defaulted to anything.

Here's a link to a (now somewhat dated) overview of RStudio addins, if it helps: https://rstudio.github.io/rstudioaddins/