Clarify broadcast text for selfupdate.
Clarify broadcast text for selfupdate.

dsyer/gvm,dsyer/gvm,gvmtool/gvm-cli,sdkman/sdkman-cli,nobeans/gvm-cli,DealerDotCom/gvm-cli,nobeans/gvm-cli,DealerDotCom/gvm-cli,skpal/sdkman-cli,shanman190/sdkman-cli,GsusRecovery/sdkman-cli,jbovet/gvm,skpal/sdkman-cli,GsusRecovery/sdkman-cli,busches/gvm-cli