fix: return missing command line nr. w/ blank line

src/config.rs

@@ -131,7 +131,9 @@ fn parse_contents(contents: String) -> Result<Vec<Hotkey>, Error> {
 
             //// Find the command
             if lines[i + 1].trim().is_empty() {
-                return Err(Error::InvalidConfig(ParseError::MissingCommand(real_line_no)));
+                return Err(Error::InvalidConfig(ParseError::MissingCommand(
+                            real_line_no + 1
+                            )));
             }
 
             let command = lines[i + 1];