Rollup merge of rust-lang#34287 - durka:patch-26, r=steveklabnik

update reference for rust-lang#29734

src/doc/reference.md

@@ -114,12 +114,20 @@ Non-doc comments are interpreted as a form of whitespace.
 
 ## Whitespace
 
-Whitespace is any non-empty string containing only the following characters:
-
+Whitespace is any non-empty string containing only characters that have the
+`Pattern_White_Space` Unicode property, namely:
+
+- `U+0009` (horizontal tab, `'\t'`)
+- `U+000A` (line feed, `'\n'`)
+- `U+000B` (vertical tab)
+- `U+000C` (form feed)
+- `U+000D` (carriage return, `'\r'`)
 - `U+0020` (space, `' '`)
-- `U+0009` (tab, `'\t'`)
-- `U+000A` (LF, `'\n'`)
-- `U+000D` (CR, `'\r'`)
+- `U+0085` (next line)
+- `U+200E` (left-to-right mark)
+- `U+200F` (right-to-left mark)
+- `U+2028` (line separator)
+- `U+2029` (paragraph separator)
 
 Rust is a "free-form" language, meaning that all forms of whitespace serve only
 to separate _tokens_ in the grammar, and have no semantic significance.