bug#28953: 11.91.0; wrong alert about inexistent LaTeX errors

[jfbu]

Hi, here is minimal example:

\documentclass{article}
\begin{document}
\typeout{Hello:1: }
\end{document}

This triggers AUCTeX log parser to report wrongly
that there were compilation errors.

The two colons and the space conspire to this result.

It happened in real life example.

Best,

Jean-François