Allow EOL in processing instructions

same fix as in https://github.com/commonmark/commonmark.js/issues/196

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - `[](url\ xxx)` is no longer a valid link.
 - Fix performance issues when parsing links (#732, #734), backticks, (#733, #736),
   emphases (#735), and autolinks (#737).
+- Allow newline in `<? ... ?>` in an inline context.
 
 
 ## [12.0.2] - 2020-10-23

lib/common/html_re.js

@@ -16,7 +16,7 @@ var open_tag    = '<[A-Za-z][A-Za-z0-9\\-]*' + attribute + '*\\s*\\/?>';
 
 var close_tag   = '<\\/[A-Za-z][A-Za-z0-9\\-]*\\s*>';
 var comment     = '<!---->|<!--(?:-?[^>-])(?:-?[^-])*-->';
-var processing  = '<[?].*?[?]>';
+var processing  = '<[?][\\s\\S]*?[?]>';
 var declaration = '<![A-Z]+\\s+[^>]*>';
 var cdata       = '<!\\[CDATA\\[[\\s\\S]*?\\]\\]>';
 

test/fixtures/markdown-it/commonmark_extras.txt

@@ -286,6 +286,16 @@ Escaped space is not allowed in link destination, commonmark/CommonMark#493.
 .
 
 
+Allow EOL in processing instructions, commonmark/commonmark.js#196.
+.
+a <?
+?>
+.
+<p>a <?
+?></p>
+.
+
+
 Coverage. Directive can terminate paragraph.
 .
 a