manual page missing ${parameter-replacement}

[Ulrich Windl]

I think the bash manual page lacks some important detail of parameter 
substitution, namely:
"Bash tests for a parameter that is unset or null. Omitting the colon results 
in a test only for a parameter that is unset."

(found in 
https://www.gnu.org/software/bash/manual/html_node/Shell-Parameter-Expansion.html)