chore: add a note about the pipe keymap and .Rproj files in the README

README.md

@@ -95,6 +95,15 @@ We changed the default key binding to insert the assignment operator (`<-`) from
 underscore (which was familiar to Emacs-ESS users) to `Alt+-` which is more
 convenient (but does not work on Vim). See the option `assign.keymap`.
 
+We added a keybinding for the pipe operator (`|>`). This defaults to 
+`<localleader>m` and is configurable with the option `pipe.keymap`.
+
+We added awareness of `.Rproj` files (the project-level configuration
+files used by RStudio). This may, for example, change whether `pipe.keymap`
+inserts `|>` or `%>%` for a particular project. See the option `proj_prioritise`
+for a full list of the behaviours which may be affected by `.Rproj` files,
+or to change whether they should affect things at all.
+
 We replaced the options `R_source` and `after_R_start` with `hook` and we can
 insert other hooks for Lua functions at other parts of the code under user
 request.