When the delimiter '@' is used in the composer, a regular expression is
built in order to suggest followers. However, if this regular expression
is incorrect, it causes a crash since RegExp will throw a syntax error.
Since a new regular expression is built for each new character the user
types, this situation can occur very easily. For example, typing '@('
will cause a crash.
This fix replaces characters which may easily lead to a syntax error by
a space.
Nicolas Martinelli
07425d407f