chore(docs): Docs for turbofish operator (noir-lang#5555)

# Description

## Problem\*

Resolves noir-lang#5254 

## Summary\*



## Additional Context



## Documentation\*

Check one:
- [ ] No documentation needed.
- [X] Documentation included in this PR.
- [ ] **[For Experimental Features]** Documentation to be submitted in a
separate PR.

# PR Checklist\*

- [X] I have tested the changes locally.
- [X] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

---------

Co-authored-by: jfecher <[email protected]>

docs/docs/noir/concepts/generics.md

@@ -104,3 +104,60 @@ impl Eq for MyStruct {
 ```
 
 You can find more details on traits and trait implementations on the [traits page](../concepts/traits.md).
+
+## Manually Specifying Generics with the Turbofish Operator
+
+There are times when the compiler cannot reasonably infer what type should be used for a generic, or when the developer themselves may want to manually distinguish generic type parameters. This is where the `::<>` turbofish operator comes into play.
+
+The `::<>` operator can follow a variable or path and can be used to manually specify generic arguments within the angle brackets.
+The name "turbofish" comes from that `::<>` looks like a little fish.
+
+Examples:
+```rust
+fn main() {
+    let mut slice = [];
+    slice = slice.push_back(1);
+    slice = slice.push_back(2);
+    // Without turbofish a type annotation would be needed on the left hand side
+    let array = slice.as_array::<2>();
+}
+```
+```rust
+fn double<let N: u32>() -> u32 {
+    N * 2
+}
+fn example() {
+    assert(double::<9>() == 18);
+    assert(double::<7 + 8>() == 30);
+}
+```
+```rust
+trait MyTrait {
+    fn ten() -> Self;
+}
+
+impl MyTrait for Field {
+    fn ten() -> Self { 10 }
+}
+
+struct Foo<T> {
+    inner: T
+}
+
+impl<T> Foo<T> {
+    fn generic_method<U>(_self: Self) -> U where U: MyTrait {
+        U::ten()
+    }
+}
+
+fn example() {
+    let foo: Foo<Field> = Foo { inner: 1 };
+    // Using a type other than `Field` here (e.g. u32) would fail as 
+    // there is no matching impl for `u32: MyTrait`. 
+    //
+    // Substituting the `10` on the left hand side of this assert
+    // with `10 as u32` would also fail with a type mismatch as we 
+    // are expecting a `Field` from the right hand side.
+    assert(10 as u32 == foo.generic_method::<Field>());
+}
+```