docs: add __state_clear intrinsic documentation to Sway Book, close #…

docs/book/src/reference/compiler_intrinsics.md

@@ -1,5 +1,24 @@
+
 # Compiler Intrinsics
 
+## `__state_clear`
+
+**Type Signature**:
+
+## `__state_clear() -> bool`
+
+The `__state_clear` intrinsic function is used to clear all entries in the contract's storage. It removes all key-value pairs from the storage, effectively resetting the contract's state to its initial empty condition. This intrinsic returns a boolean value: `true` if the operation was successful, and `false` if it failed for any reason.
+
+### Example
+
+```sway
+fn reset_contract_storage() -> bool {
+    // Clear all storage and return the result
+    __state_clear()
+}
+
+```
+
 The Sway compiler supports a list of intrinsics that perform various low level operations that are useful for building libraries. Compiler intrinsics should rarely be used but are preferred over `asm` blocks because they are type-checked and are safer overall. Below is a list of all available compiler intrinsics:
 
 ---