docs: implement Miguel's feedback

subjects/arrange_it/README.md

@@ -4,6 +4,7 @@
 
 Create a **function** named `arrange_phrase`, that takes a string literal, _sorts_ the words and returns it. Each word will contain a number that indicates the position of that word.
 
+### Expected Functions
 ```rust
 pub fn arrange_phrase(phrase: &str) -> String {
 }

subjects/borrow/README.md

@@ -4,6 +4,7 @@
 
 Create a **function** named `str_len`, you'll need to complete the function signature. Your function should accept a string or a string literal, and return its length without taking ownership of the value (i.e, borrowing the value).
 
+### Expected functions
 ```rust
 pub fn str_len(s: ) -> usize {
 }

subjects/borrow_me_the_reference/README.md

@@ -11,7 +11,6 @@ Create the following functions:
 - `is_correct`: which borrows a Vector of string literals representing simple addition and subtraction equations. The function should replace the correct equations with `✔`, and the wrong ones with `✘`. It should return a `usize` with the percentage of correct equations.
 
 ### Expected Functions
-
 ```rust
 pub fn delete_and_backspace(s: &mut String) {
 }

subjects/copy/README.md

@@ -15,6 +15,7 @@ Create the following **functions**. The objective is to know how ownership works
   - with the `original` value.
   - and the `natural logarithm` of each `absolute` value.
 
+### Expected functions
 ```rust
 pub fn nbr_function(c: i32) -> (i32, f64, f64) {
 }

subjects/doubtful/README.md

@@ -4,6 +4,7 @@
 
 Create a function named `doubtful` which appends a question mark to every string passed to it. It must not return a value.
 
+### Expected functions
 ```rust
 pub fn doubtful(s: /*give the correct type*/ ) {
 }

subjects/name_initials/README.md

@@ -4,6 +4,7 @@
 
 Create a **function** named `initials`. This function will receive a vector of string literals with names, and return a vector of Strings with the initials of each name.
 
+### Expected Functions
 ```rust
 pub fn initials(names: Vec<&str>) -> Vec<String> {
 }

subjects/ownership/README.md

@@ -4,6 +4,7 @@
 
 Create a **function** named `first_subword`, that takes ownership of a string and returns the first sub-word in it. It should work for `camelCase`, `PascalCase`, and `snake_case`.
 
+### Expected functions
 ```rust
 pub fn first_subword(mut s: String) -> String {
 }

subjects/string_literals/README.md

@@ -8,8 +8,9 @@ Create the following functions:
 - `is_ascii`: that returns `true` if all characters are within the ASCII range.
 - `contains`: that returns `true` if the string contains the given pattern.
 - `split_at`: that divides a string in two returning a tuple.
-- `find`: that returns the index if the first character of a given string that matches the pattern.
+- `find`: that returns the index of the first character of a given string that matches the pattern.
 
+### Expected functions
 ```rust
 pub fn is_empty(v: &str) -> bool {
 }

subjects/tic_tac_toe/README.md

@@ -6,14 +6,14 @@ You must create some functions for a tic-tac-toe checker.
 
 Create a function named `tic_tac_toe`, which receives a tic-tac-toe table. It should return the appropriate string: `"player O won"`, `"player X won"` or `"Tie"`.
 
-```rust
-pub fn tic_tac_toe(table: Vec<Vec<&str>>) -> String {
-}
-```
 
 Also create the following functions, which each accept a player and a table. These functions should return `true` if the player has completed one of the diagonals, rows or columns:
 
+### Expected functions
 ```rust
+pub fn tic_tac_toe(table: Vec<Vec<&str>>) -> String {
+}
+
 pub fn diagonals(player: &str, table: &Vec<Vec<&str>>) -> bool {
 }
 

subjects/to_url/README.md

@@ -4,6 +4,7 @@
 
 Create a **function** named `to_url` which takes a string and substitutes every white-space with `"%20"`.
 
+### Expected functions
 ```rust
 pub fn to_url(s: &str) -> String {
 }