Mute unavoidable ShellCheck warnings

dotfiles/bash/post.bashrc

 ### things to do AFTER host/user-specific settings ###
 ######################################################
 
+#shellcheck disable=2120
 __bashum__lastrv() {
     local rvfile        # path to return value cache file
     local lastrv        # actual last return value
     echo -n "|$ctx"
 }
 
+#shellcheck disable=SC2154 disable=2016
 __bashum__mkps1() {
     # these functions must be already defined by ~/.bash/user/*.bashrc
     # and ~/.bash/host/*.bashrc
     echo '$ '                               # obligatory dollar
 }
 
+#shellcheck disable=SC2154
 __bashum__mkps2() {
     echo "$white>$yellow>$lyellow>$normal "
 }
     esac
 }
 
+#shellcheck disable=SC2016
 __bashum__mkpc() {
     #
     # Compose PROMPT_COMMAND body