show interface for member functions

[krlmlr]

• for print and format for both R6 and R6ClassGenerator
• first line only
• no width restriction

> cl <- R6Class("cl", public = list(cat = cat))
> cl
<cl> object generator
  Public:
    cat: function (..., file = "", sep = " ", fill = FALSE, labels = NULL, 
    clone: function (deep = FALSE) 
  Parent env: <environment: R_GlobalEnv>
  Locked objects: TRUE
  Locked class: FALSE
  Portable: TRUE
> cl$new()
<cl>
  Public:
    cat: function (..., file = "", sep = " ", fill = FALSE, labels = NULL, 
    clone: function (deep = FALSE) 

[wch]

Thanks!