Added filename to top of .rs files

move_semantics/move_semantics1.rs

@@ -1,3 +1,4 @@
+// move_semantics1.rs
 // Make me compile! Scroll down for hints :)
 
 pub fn main() {

move_semantics/move_semantics2.rs

@@ -1,3 +1,4 @@
+// move_semantics2.rs
 // Make me compile without changing line 9! Scroll down for hints :)
 
 pub fn main() {

move_semantics/move_semantics3.rs

@@ -1,3 +1,4 @@
+// move_semantics3.rs
 // Make me compile without adding new lines-- just changing existing lines!
 // (no lines with multiple semicolons necessary!)
 // Scroll down for hints :)

move_semantics/move_semantics4.rs

@@ -1,3 +1,4 @@
+// move_semantics4.rs
 // Refactor this code so that instead of having `vec0` and creating the vector
 // in `fn main`, we instead create it within `fn fill_vec` and transfer the
 // freshly created vector from fill_vec to its caller. Scroll for hints!