Revert "Reformat whitespace list for consistency"

This reverts commit 60eb145.

This re-formats our Whitespace to be centered on Unicode's defintion.

This makes it easy to compare with the standard and helps with
Frontmatter.
Unlike regular Rust, Frontmatter cares about the type of Whitespace.
Even if we want to duplicate the definition, having them formatted
similarly makes them easy to compare.

Author: epage

src/whitespace.md

@@ -4,23 +4,26 @@ r[lex.whitespace]
 r[whitespace.syntax]
 ```grammar,lexer
 @root WHITESPACE ->
-      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+0085 // Next line
-    | U+200E // Left-to-right mark
-    | U+200F // Right-to-left mark
-    | U+2028 // Line separator
-    | U+2029 // Paragraph separator
-
-TAB -> U+0009 // Horizontal tab, `'\t'`
-
-LF -> U+000A  // Line feed, `'\n'`
-
-CR -> U+000D  // Carriage return, `'\r'`
+    // end of line
+      LF
+    | U+000B // vertical tabulation
+    | U+000C // form feed
+    | CR
+    | U+0085 // Unicode next line
+    | U+2028 // Unicode LINE SEPARATOR
+    | U+2029 // Unicode PARAGRAPH SEPARATOR
+    // Ignorable Code Point
+    | U+200E // Unicode LEFT-TO-RIGHT MARK
+    | U+200F // Unicode RIGHT-TO-LEFT MARK
+    // horizontal whitespace
+    | TAB
+    | U+0020  // space ' '
+
+TAB -> U+0009  // horizontal tab ('\t')
+
+LF -> U+000A  // line feed ('\n')
+
+CR -> U+000D  // carriage return ('\r')
 ```
 
 r[lex.whitespace.intro]