chore(hints): update hints to be consistent

added hint for tests3 and formatted other hints

info.toml

@@ -51,6 +51,7 @@ using a special keyword. Unfortunately this doesn't help us much in this exercis
 because we want to assign a different typed value to an existing variable. Sometimes
 you may also like to reuse existing variable names because you are just converting
 values to different types like in this exercise.
+
 Fortunately Rust has a powerful solution to this problem: 'Shadowing'!
 You can read more about 'Shadowing' in the book's section 'Variables and Mutability':
 https://doc.rust-lang.org/book/ch03-01-variables-and-mutability.html#shadowing
@@ -146,7 +147,7 @@ For that first compiler error, it's important in Rust that each conditional
 block return the same type! To get the tests passing, you will need a couple
 conditions checking different input values."""
 
-# TEST 1
+# QUIZ 1
 
 [[exercises]]
 name = "quiz1"
@@ -202,6 +203,7 @@ mode = "compile"
 hint = """
 Stop reading whenever you feel like you have enough direction :) Or try
 doing one step and then fixing the compiler errors that result!
+
 So the end goal is to:
    - get rid of the first line in main that creates the new vector
    - so then `vec0` doesn't exist, so we can't pass it to `fill_vec`
@@ -425,7 +427,7 @@ Yes, it would be really easy to fix this by just changing the value bound to `wo
 string slice instead of a `String`, wouldn't it?? There is a way to add one character to line
 9, though, that will coerce the `String` into a string slice."""
 
-# TEST 2
+# QUIZ 2
 
 [[exercises]]
 name = "quiz2"
@@ -484,13 +486,11 @@ at the test helper function `test_with_str`, since it returns whatever
 `read_and_validate` returns and `test_with_str` has its signature fully
 specified.
 
-
 Next hint: There are three places in `read_and_validate` that we call a
 function that returns a `Result` (that is, the functions might fail).
 Apply the `?` operator on those calls so that we return immediately from
 `read_and_validate` if those function calls fail.
 
-
 Another hint: under the hood, the `?` operator calls `From::from`
 on the error value to convert it to a boxed trait object, a Box<dyn error::Error>,
 which is polymorphic-- that means that lots of different kinds of errors
@@ -499,20 +499,18 @@ since they all implement the `error::Error` trait.
 Check out this section of the book:
 https://doc.rust-lang.org/book/ch09-02-recoverable-errors-with-result.html#a-shortcut-for-propagating-errors-the--operator
 
-
 Another another hint: Note that because the `?` operator returns
 the *unwrapped* value in the `Ok` case, if we want to return a `Result` from
 `read_and_validate` for *its* success case, we'll have to rewrap a value
 that we got from the return value of a `?`ed call in an `Ok`-- this will
 look like `Ok(something)`.
 
-
 Another another another hint: `Result`s must be "used", that is, you'll
 get a warning if you don't handle a `Result` that you get in your
 function. Read more about that in the `std::result` module docs:
 https://doc.rust-lang.org/std/result/#results-must-be-used"""
 
-# Generics
+# GENERICS
 
 [[exercises]]
 name = "generics1"
@@ -639,9 +637,10 @@ mode = "test"
 hint = """
 You can call a function right where you're passing arguments to `assert!` -- so you could do
 something like `assert!(having_fun())`. If you want to check that you indeed get false, you
-can negate the result of what you're doing using `!`, like `assert!(!having_fun())`."""
+can negate the result of what you're doing using `!`, like `assert!(!having_fun())`.
 
-# TEST 3
+To test if 2 arguments are equal, you can use the macro `assert_eq!()` (eq = equal). To test if
+2 arguments differ, you can use the macro `assert_ne!()` (ne = not equal)"""
 
 [[exercises]]
 name = "quiz3"
@@ -686,6 +685,8 @@ is too much of a struggle, consider reading through all of Chapter 16 in the boo
 https://doc.rust-lang.org/stable/book/ch16-00-concurrency.html
 """
 
+# ITERATORS
+
 [[exercises]]
 name = "iterators1"
 path = "exercises/standard_library_types/iterators1.rs"
@@ -695,8 +696,10 @@ Step 1:
 We need to apply something to the collection `my_fav_fruits` before we start to go through
 it. What could that be? Take a look at the struct definition for a vector for inspiration:
 https://doc.rust-lang.org/std/vec/struct.Vec.html.
+
 Step 2 & step 2.1:
 Very similar to the lines above and below. You've got this!
+
 Step 3:
 An iterator goes through all elements in a collection, but what if we've run out of
 elements? What should we expect here? If you're stuck, take a look at
@@ -779,14 +782,12 @@ mutate the data at a time. Take a look at this section of the book:
 https://doc.rust-lang.org/book/ch16-03-shared-state.html#atomic-reference-counting-with-arct
 and keep reading if you'd like more hints :)
 
-
 Do you now have an `Arc` `Mutex` `JobStatus` at the beginning of main? Like:
 `let status = Arc::new(Mutex::new(JobStatus { jobs_completed: 0 }));`
 Similar to the code in the example in the book that happens after the text
 that says "We can use Arc<T> to fix this.". If not, give that a try! If you
 do and would like more hints, keep reading!!
 
-
 Make sure neither of your threads are holding onto the lock of the mutex
 while they are sleeping, since this will prevent the other thread from
 being allowed to get the lock. Locks are automatically released when
@@ -846,7 +847,7 @@ You only need to add a single character to make this compile.
 The way macros are written, it wants to see something between each
 "macro arm", so it can separate them."""
 
-# TEST 4
+# QUIZ 4
 
 [[exercises]]
 name = "quiz4"