update documentation to reflect change to read_delim API

R/source.R

@@ -9,9 +9,9 @@
 #'    downloaded. Remote gz files can also be automatically downloaded and
 #'    decompressed.
 #'
-#'    Literal data is most useful for examples and tests. It must contain at
-#'    least one new line to be recognised as data (instead of a path) or be a
-#'    vector of greater than length 1.
+#'    Literal data is most useful for examples and tests. To be recognised as a
+#'    path, it must be wrapped with `I()`, be a string containing at least one
+#'    new line, or be a vector containing at least one string with a new line.
 #'
 #'    Using a value of [clipboard()] will read from the system clipboard.
 #'