docs: cleanup the explanation paragraphs at the start of each exercise.

exercises/modules/modules1.rs

@@ -1,5 +1,7 @@
 // modules1.rs
-// Execute `rustlings hint modules1` or use the `hint` watch subcommand for a hint.
+//
+// Execute `rustlings hint modules1` or use the `hint` watch subcommand for a
+// hint.
 
 // I AM NOT DONE
 

exercises/modules/modules2.rs

@@ -1,7 +1,11 @@
 // modules2.rs
-// You can bring module paths into scopes and provide new names for them with the
-// 'use' and 'as' keywords. Fix these 'use' statements to make the code compile.
-// Execute `rustlings hint modules2` or use the `hint` watch subcommand for a hint.
+//
+// You can bring module paths into scopes and provide new names for them with
+// the 'use' and 'as' keywords. Fix these 'use' statements to make the code
+// compile.
+//
+// Execute `rustlings hint modules2` or use the `hint` watch subcommand for a
+// hint.
 
 // I AM NOT DONE
 

exercises/modules/modules3.rs

@@ -1,9 +1,12 @@
 // modules3.rs
-// You can use the 'use' keyword to bring module paths from modules from anywhere
-// and especially from the Rust standard library into your scope.
-// Bring SystemTime and UNIX_EPOCH
-// from the std::time module. Bonus style points if you can do it with one line!
-// Execute `rustlings hint modules3` or use the `hint` watch subcommand for a hint.
+//
+// You can use the 'use' keyword to bring module paths from modules from
+// anywhere and especially from the Rust standard library into your scope. Bring
+// SystemTime and UNIX_EPOCH from the std::time module. Bonus style points if
+// you can do it with one line!
+//
+// Execute `rustlings hint modules3` or use the `hint` watch subcommand for a
+// hint.
 
 // I AM NOT DONE