docs: fix simple typo, signalls -> signals
docs: fix simple typo, signalls -> signals

There is a small typo in src/util/dispatch.c.

Should read `signals` rather than `signalls`.

Signed-off-by: David Rheinsberg <1e7ff67ac6e6692b085f67edeb10803d9022c525@gmail.com>

bus1/dbus-broker