feat: Terminate $PROMPT_COMMAND properly (starship#799)

Add trailing semicolon to end $PROMPT_COMMAND properly.
This will prevent starship_precmd to accidentally mess with other hooks invoked after it.

src/init/starship.bash

@@ -71,10 +71,10 @@ else
         PROMPT_COMMAND="starship_precmd"
     elif [[ "$PROMPT_COMMAND" != *"starship_precmd" ]]; then
         # Remove any trailing semicolon before appending (PR #784)
-        PROMPT_COMMAND="${PROMPT_COMMAND%;};starship_precmd"
+        PROMPT_COMMAND="${PROMPT_COMMAND%;};starship_precmd;"
     fi
 fi
 
 # Set up the start time and STARSHIP_SHELL, which controls shell-specific sequences
 STARSHIP_START_TIME=$(::STARSHIP:: time)
-export STARSHIP_SHELL="bash"
+export STARSHIP_SHELL="bash"