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

exercises/primitive_types/primitive_types1.rs

@@ -1,6 +1,10 @@
 // primitive_types1.rs
-// Fill in the rest of the line that has code missing!
-// No hints, there's no tricks, just get used to typing these :)
+//
+// Fill in the rest of the line that has code missing! No hints, there's no
+// tricks, just get used to typing these :)
+//
+// Execute `rustlings hint primitive_types1` or use the `hint` watch subcommand
+// for a hint.
 
 // I AM NOT DONE
 

exercises/primitive_types/primitive_types2.rs

@@ -1,6 +1,10 @@
 // primitive_types2.rs
-// Fill in the rest of the line that has code missing!
-// No hints, there's no tricks, just get used to typing these :)
+//
+// Fill in the rest of the line that has code missing! No hints, there's no
+// tricks, just get used to typing these :)
+//
+// Execute `rustlings hint primitive_types2` or use the `hint` watch subcommand
+// for a hint.
 
 // I AM NOT DONE
 

exercises/primitive_types/primitive_types3.rs

@@ -1,6 +1,9 @@
 // primitive_types3.rs
+//
 // Create an array with at least 100 elements in it where the ??? is.
-// Execute `rustlings hint primitive_types3` or use the `hint` watch subcommand for a hint.
+//
+// Execute `rustlings hint primitive_types3` or use the `hint` watch subcommand
+// for a hint.
 
 // I AM NOT DONE
 

exercises/primitive_types/primitive_types4.rs

@@ -1,6 +1,9 @@
 // primitive_types4.rs
+//
 // Get a slice out of Array a where the ??? is so that the test passes.
-// Execute `rustlings hint primitive_types4` or use the `hint` watch subcommand for a hint.
+//
+// Execute `rustlings hint primitive_types4` or use the `hint` watch subcommand
+// for a hint.
 
 // I AM NOT DONE
 

exercises/primitive_types/primitive_types5.rs

@@ -1,6 +1,9 @@
 // primitive_types5.rs
+//
 // Destructure the `cat` tuple so that the println will work.
-// Execute `rustlings hint primitive_types5` or use the `hint` watch subcommand for a hint.
+//
+// Execute `rustlings hint primitive_types5` or use the `hint` watch subcommand
+// for a hint.
 
 // I AM NOT DONE
 

exercises/primitive_types/primitive_types6.rs

@@ -1,7 +1,10 @@
 // primitive_types6.rs
-// Use a tuple index to access the second element of `numbers`.
-// You can put the expression for the second element where ??? is so that the test passes.
-// Execute `rustlings hint primitive_types6` or use the `hint` watch subcommand for a hint.
+//
+// Use a tuple index to access the second element of `numbers`. You can put the
+// expression for the second element where ??? is so that the test passes.
+//
+// Execute `rustlings hint primitive_types6` or use the `hint` watch subcommand
+// for a hint.
 
 // I AM NOT DONE