docs: Align BuiltinHintProcessor README with current cairo-vm API

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 #### Upcoming Changes
 
+* docs: align BuiltinHintProcessor documentation with current implementation [#2274](https://github.com/lambdaclass/cairo-vm/pull/2274)
+
 #### [3.0.0] - 2025-11-19
 
 #### [3.0.0-rc.5] - 2025-11-14

docs/hint_processor/builtin_hint_processor/README.md

@@ -27,12 +27,12 @@ For this step, you will have to code your hint implementation as a Rust function
 The hint implementation must also follow a specific structure in terms of variable input and output:
 ```rust
 fn hint_func(
-    vm: &mut VM,
+    vm: &mut VirtualMachine,
     exec_scopes: &mut ExecutionScopes,
     ids_data: &HashMap<String, HintReference>,
     ap_tracking: &ApTracking,
-    constants: &HashMap<String, BigInt>,
-) -> Result<(), VirtualMachineError> {
+    constants: &HashMap<String, Felt252>,
+) -> Result<(), HintError> {
     // Your implementation
 }
 
@@ -43,12 +43,12 @@ For example, this function implements the hint "print(ids.a)":
 
 ```rust
 fn print_a_hint(
-    vm: &mut VM,
+    vm: &mut VirtualMachine,
     exec_scopes: &mut ExecutionScopes,
     ids_data: &HashMap<String, HintReference>,
     ap_tracking: &ApTracking,
-    constants: &HashMap<String, BigInt>,
-) -> Result<(), VirtualMachineError> {
+    constants: &HashMap<String, Felt252>,
+) -> Result<(), HintError> {
     let a = get_integer_from_var_name("a", vm, ids_data, ap_tracking)?;
     println!("{}", a);
     Ok(())
@@ -61,22 +61,43 @@ let hint = HintFunc(Box::new(print_a_hint));
 Import the BuiltinHintProcessor from cairo-vm, instantiate it using the `new_empty()` method and the add your custom hint implementation using the method `add_hint`
 ```rust
 use cairo_vm::hint_processor::builtin_hint_processor::builtin_hint_processor_definition::BuiltinHintProcessor
+use std::rc::Rc;
 
 let mut hint_processor = BuiltinHintProcessor::new_empty();
-hint_processor.add_hint(String::from("print(ids.a)"), hint);
+hint_processor.add_hint(String::from("print(ids.a)"), Rc::new(hint));
+```
+You can also create a dictionary of `Rc<HintFunc>` and use the method `new()` to create a `BuiltinHintProcessor` with a preset dictionary of functions instead of using `add_hint()` for each custom hint. Note that `new()` also requires a `RunResources` instance:
+```rust
+use cairo_vm::vm::runners::cairo_runner::RunResources;
+use std::collections::HashMap;
+use std::rc::Rc;
+
+let mut map: HashMap<String, Rc<HintFunc>> = HashMap::new();
+map.insert(String::from("print(ids.a)"), Rc::new(hint));
+let hint_processor = BuiltinHintProcessor::new(map, RunResources::default());
 ```
-You can also create a dictionary of HintFunc and use the method `new()` to create a BuiltinHintProcessor with a preset dictionary of functions instead of using `add_hint()` for each custom hint.
 
 #### Step 4: Run your cairo program using BuiltinHintProcessor extended with your hint
 Import the function cairo_run from cairo-vm, and run your compiled program
 
 ```rust
-use cairo_vm::cairo_run::cairo_run;
+use cairo_vm::cairo_run::{cairo_run, CairoRunConfig};
+use cairo_vm::types::layout_name::LayoutName;
+use std::fs::File;
+use std::io::{BufReader, Read};
+use std::path::Path;
+
+let file = File::open(Path::new("custom_hint.json")).expect("Couldn't load file");
+let mut reader = BufReader::new(file);
+let mut buffer = Vec::<u8>::new();
+reader.read_to_end(&mut buffer).expect("Couldn't read file");
+
 cairo_run(
-        Path::new("custom_hint.json"),
-        "main",
-        false,
-        false,
+        &buffer,
+        &CairoRunConfig {
+            layout: LayoutName::all_cairo,
+            ..Default::default()
+        },
         &mut hint_processor,
     )
     .expect("Couldn't run program");
@@ -125,11 +146,11 @@ There are also some helpers that dont depend on the hint processor used that can
 You can also find plenty of example implementations in the [builtin hint processor folder](../../../vm/src/hint_processor/builtin_hint_processor).
 
 ### Error Handling
-This API uses VirtualMachineError as error return type for hint functions, while its not possible to add error types to VirtualMachineError, you can use VirtualMachineError::CustomHint which receives a string and prints an error message with the format: "Hint Error: [your message]".
-For example, if we want our hint to return an error if ids.a is less than 0 we could write:
+This API uses `HintError` as error return type for hint functions. To return a custom error, use `HintError::CustomHint`, which receives a string and prints an error message with the format: "Hint Error: [your message]".
+For example, if we want our hint to return an error if `ids.a` is less than 0 we could write:
 
 ```rust
-if (get_integer_from_var_name("a", vm, ids_data, ap_tracking)? < 0){
-  return Err(VirtualMachineError::CustomHint(String::from("a < 0")))
+if get_integer_from_var_name("a", vm, ids_data, ap_tracking)? < 0 {
+  return Err(HintError::CustomHint("a < 0".into()));
 }
 ```