Update-core.php small validation fix.

[Simek]

Update-core.php small validation fix.

[ryan]

I think we should fix it without the string change for 2.9.1. I like to avoid changing translated strings in maintenance releases when possible.

[Simek]

You have right. Only non closed paragraph generate validation error. I've corrected the double space instinctively.

[ryan]

(In [12498]) Validation fix. Props Simek. fixes #11560 for 2.9

[ryan]

[12497] for trunk.

[ryan]

I left the space change in for trunk and left it out for 2.9.1.