widget/reply: formatting syntax for _italics_

Single underscores for emphasis, as in mail, chat, and Markdown.
Do not cater to advanced usage like partial highlights inside words and
escapes (neither do whatsapp and slack for example); admins can use html
if really needed.

diff --git a/upload.inc.php b/upload.inc.php
index 7810ff6e613da2e065264ae954c291a08b72f383..10881a24a0f9317216339e0b88dc65232afc0207 100644 (file)
--- a/upload.inc.php
+++ b/upload.inc.php
@@ -52,8 +52,8 @@ function messagehtml($input)
                return $input;  # allow html input as is if privileged
        }
        $html = preg_replace(
-               ["/\r\n?/", "/  +\n/", "/\n/"],
-               ["\n",      "<br />",  "</p>\n<p>"],
+               ["/\r\n?/", "/  +\n/", "/\n/",      '/\b_(\w+)_\b/'],
+               ["\n",      "<br />",  "</p>\n<p>", '<em>$1</em>'  ],
                htmlspecialchars($input)
        );
        return "<p>$html</p>";