Remove Mozilla specific references (#24)

We kinda branded the talk when we held it at the Mozilla Switzerland
meetup.  But for other occurrences this doesn't make any sense.

Author: rnestler

sections/4.2-ownership.tex

@@ -136,7 +136,7 @@ \subsection{Promise 2: No dangling pointers}
 
 \begin{minted}{rust}
 fn print_loud(text: String) { println!("{}!!!!!", text); }
-let s = "Hello, Mozillians".to_string();
+let s = "Hello, Hackers".to_string();
 print_loud(s);
 println!("{}", s);
 \end{minted}
@@ -164,7 +164,7 @@ \subsection{Promise 2: No dangling pointers}
 
 \begin{minted}{rust}
 fn print_loud(text: &String) { println!("{}!!!!!", text); }
-let s = "Hello, Mozillians".to_string();
+let s = "Hello, Hackers".to_string();
 print_loud(&s);
 println!("Original value was {}", s);
 \end{minted}
@@ -181,7 +181,7 @@ \subsection{Promise 2: No dangling pointers}
 
 \begin{minted}{rust}
 fn make_loud(text: &mut String) { text.push_str("!!!!!"); };
-let mut s = "Hello, Mozillians".to_string();
+let mut s = "Hello, Hackers".to_string();
 make_loud(&mut s);
 println!("New value is {}", s);
 \end{minted}