[mantisbt-dev] Revised error message for #2800

[Damien R. <dam...@me...>]

The current message for this error is:

Invalid form security token. Did you submit the form twice by accident?

In light of the number of issues related to this error, and my personal 
experience showing that in most cases it does NOT occur due to multiple 
form submissions but because of a timeout of the PHP session, I think we 
should reword this error message to mention that fact.

Proposed alternatives (see #14122):

Invalid form security token. This may happen if you submitted the form 
twice by accident, or because your session has timed out.

Invalid form security token. This could be caused by accidentally 
submitting the form twice, or by a session timeout.

Thoughts, comments ?

Damien