Correct docstring for @__FILE__ ref #12727

Author: ihnorton

base/docs/helpdb.jl

@@ -9929,8 +9929,7 @@ keywords[symbol("@__FILE__")] = doc"""
 
     @__FILE__() -> AbstractString
 
-`@__FILE__` expands to a string with the absolute path and file name of the script being run.
-Returns `"none"` if run from a REPL or command-line context.
+`@__FILE__` expands to a string with the absolute path and file name of the script being run. Returns `nothing` if run from a REPL or an empty string if evaluated by `julia -e <expr>`.
 """
 
 keywords[symbol("@__LINE__")] = doc"""