help nudge

Author: MichaelChirico

R/data.table.R

@@ -686,7 +686,7 @@ replace_dot_alias = function(e) {
     if (is.null(jsub)) return(NULL)
 
     if (!with) {
-      if (jsub %iscall% ":=") stopf("`:=` is only supported under with=TRUE.")
+      if (jsub %iscall% ":=") stopf("`:=` is only supported under with=TRUE, see ?`:=`.")
       # missingby was already checked above before dealing with i
       if (jsub %iscall% c("!", "-") && length(jsub)==2L) {  # length 2 to only match unary, #2109
         notj = TRUE