Use Line_Separator and Paragraph_Separator for unsupported environment like cloudflare pages

Author: hsbt

lib/rdoc/markdown/literals.kpeg

@@ -16,6 +16,6 @@
 Alphanumeric      = /\p{Word}/
 AlphanumericAscii = /[A-Za-z0-9]/
 BOM               = "\uFEFF"
-Newline           = /\n|\r\n?|\p{Zl}|\p{Zp}/
+Newline           = /\n|\r\n?|\p{Line_Separator}|\p{Paragraph_Separator}/
 NonAlphanumeric   = /\p{^Word}/
 Spacechar         = /\t|\p{Zs}/