Remove stable from book links

exercises/04_primitive_types/README.md

@@ -5,5 +5,5 @@ compiler. In this section, we'll go through the most important ones.
 
 ## Further information
 
-- [Data Types](https://doc.rust-lang.org/stable/book/ch03-02-data-types.html)
+- [Data Types](https://doc.rust-lang.org/book/ch03-02-data-types.html)
-- [The Slice Type](https://doc.rust-lang.org/stable/book/ch04-03-slices.html)
+- [The Slice Type](https://doc.rust-lang.org/book/ch04-03-slices.html)

exercises/05_vecs/README.md

@@ -12,6 +12,6 @@ the other useful data structure, hash maps, later.
 
 ## Further information
 
-- [Storing Lists of Values with Vectors](https://doc.rust-lang.org/stable/book/ch08-01-vectors.html)
+- [Storing Lists of Values with Vectors](https://doc.rust-lang.org/book/ch08-01-vectors.html)
 - [`iter_mut`](https://doc.rust-lang.org/std/primitive.slice.html#method.iter_mut)
 - [`map`](https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.map)

exercises/12_options/README.md

@@ -14,7 +14,7 @@ Option types are very common in Rust code, as they have a number of uses:
 
 ## Further Information
 
-- [Option Enum Format](https://doc.rust-lang.org/stable/book/ch10-01-syntax.html#in-enum-definitions)
+- [Option Enum Format](https://doc.rust-lang.org/book/ch10-01-syntax.html#in-enum-definitions)
 - [Option Module Documentation](https://doc.rust-lang.org/std/option/)
 - [Option Enum Documentation](https://doc.rust-lang.org/std/option/enum.Option.html)
 - [if let](https://doc.rust-lang.org/rust-by-example/flow_control/if_let.html)

exercises/14_generics/README.md

@@ -7,5 +7,5 @@ The simplest and most common use of generics is for type parameters.
 
 ## Further information
 
-- [Generic Data Types](https://doc.rust-lang.org/stable/book/ch10-01-syntax.html)
+- [Generic Data Types](https://doc.rust-lang.org/book/ch10-01-syntax.html)
 - [Bounds](https://doc.rust-lang.org/rust-by-example/generics/bounds.html)

rustlings-macros/info.toml

@@ -309,7 +309,7 @@ In Rust, there are two ways to define a Vector.
    inside the square brackets. This way is simpler when you exactly know
    the initial values.
 
-Check this chapter: https://doc.rust-lang.org/stable/book/ch08-01-vectors.html
+Check this chapter: https://doc.rust-lang.org/book/ch08-01-vectors.html
 of the Rust book to learn more."""
 
 [[exercises]]
@@ -378,7 +378,7 @@ dir = "06_move_semantics"
 test = false
 hint = """
 To find the answer, you can consult the book section "References and Borrowing":
-https://doc.rust-lang.org/stable/book/ch04-02-references-and-borrowing.html
+https://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html
 
 The first problem is that `get_char` is taking ownership of the string. So
 `data` is moved and can't be used for `string_uppercase`. `data` is moved to
@@ -416,7 +416,7 @@ to its fields.
 
 There are however some shortcuts that can be taken when instantiating structs.
 Have a look in The Book to find out more:
-https://doc.rust-lang.org/stable/book/ch05-01-defining-structs.html#creating-instances-from-other-instances-with-struct-update-syntax"""
+https://doc.rust-lang.org/book/ch05-01-defining-structs.html#creating-instances-from-other-instances-with-struct-update-syntax"""
 
 [[exercises]]
 name = "structs3"
@@ -487,7 +487,7 @@ to add one character to the `if` statement, though, that will coerce the
 Side note: If you're interested in learning about how this kind of reference
 conversion works, you can jump ahead in the book and read this part in the
 smart pointers chapter:
-https://doc.rust-lang.org/stable/book/ch15-02-deref.html#implicit-deref-coercions-with-functions-and-methods"""
+https://doc.rust-lang.org/book/ch15-02-deref.html#implicit-deref-coercions-with-functions-and-methods"""
 
 [[exercises]]
 name = "strings3"
@@ -561,7 +561,7 @@ hint = """
 Use the `entry()` and `or_insert()` methods of `HashMap` to achieve this.
 
 Learn more in The Book:
-https://doc.rust-lang.org/stable/book/ch08-03-hash-maps.html#only-inserting-a-value-if-the-key-has-no-value"""
+https://doc.rust-lang.org/book/ch08-03-hash-maps.html#only-inserting-a-value-if-the-key-has-no-value"""
 
 [[exercises]]
 name = "hashmaps3"
@@ -572,7 +572,7 @@ Hint 1: Use the `entry()` and `or_insert()` (or `or_insert_with()`) methods of
         exist in the table yet.
 
 Learn more in The Book:
-https://doc.rust-lang.org/stable/book/ch08-03-hash-maps.html#only-inserting-a-value-if-the-key-has-no-value
+https://doc.rust-lang.org/book/ch08-03-hash-maps.html#only-inserting-a-value-if-the-key-has-no-value
 
 Hint 2: If there is already an entry for a given key, the value returned by
         `entry()` can be updated based on the existing value.
@@ -739,7 +739,7 @@ name = "generics2"
 dir = "14_generics"
 hint = """
 Related section in The Book:
-https://doc.rust-lang.org/stable/book/ch10-01-syntax.html#in-method-definitions"""
+https://doc.rust-lang.org/book/ch10-01-syntax.html#in-method-definitions"""
 
 # TRAITS
 
@@ -871,7 +871,7 @@ We expect the method `Rectangle::new` to panic for negative values.
 To handle that, you need to add a special attribute to the test function.
 
 You can refer to the docs:
-https://doc.rust-lang.org/stable/book/ch11-01-writing-tests.html#checking-for-panics-with-should_panic"""
+https://doc.rust-lang.org/book/ch11-01-writing-tests.html#checking-for-panics-with-should_panic"""
 
 # STANDARD LIBRARY TYPES
 
@@ -1007,7 +1007,7 @@ thread-local copy of the numbers.
 This is a simple exercise if you understand the underlying concepts, but if this
 is too much of a struggle, consider reading through all of Chapter 16 in The
 Book:
-https://doc.rust-lang.org/stable/book/ch16-00-concurrency.html"""
+https://doc.rust-lang.org/book/ch16-00-concurrency.html"""
 
 [[exercises]]
 name = "cow1"