[Docs] Update diagram & wording for pointer API changes.

Follow-up to #3080, updating the
diagram and some wording to match the new UnsafePointer APIs.

MODULAR_ORIG_COMMIT_REV_ID: 01d145d8a4dbba6471fc03dd199d7bdad6fcd3c3

docs/manual/pointers.ipynb

@@ -199,18 +199,17 @@
     "\n",
     "### Initializing the pointee\n",
     "\n",
-    "The `unsafe_pointer` module includes a number of free functions for working with\n",
-    "the `UnsafePointer` type. To initialize allocated memory, you can use the \n",
+    "To initialize allocated memory, `UnsafePointer` provides the\n",
     "[`init_pointee_copy()`](/mojo/stdlib/memory/unsafe_pointer/UnsafePointer#init_pointee_copy)\n",
-    "or [`init_pointee_move()`](/mojo/stdlib/memory/unsafe_pointer/UnsafePointer#init_pointee_move)\n",
-    "functions:\n",
+    "and [`init_pointee_move()`](/mojo/stdlib/memory/unsafe_pointer/UnsafePointer#init_pointee_move)\n",
+    "methods. For example:\n",
     "\n",
     "```mojo\n",
-    "ptr.init_pointee_copy(5)\n",
+    "ptr.init_pointee_copy(my_value)\n",
     "```\n",
     "\n",
     "To move a value into the pointer's memory location, use\n",
-    "`init_pointee_move`:\n",
+    "`init_pointee_move()`:\n",
     "\n",
     "```mojo\n",
     "str_ptr.init_pointee_move(my_string^)\n",
@@ -381,20 +380,20 @@
     "\n",
     "The \n",
     "[`take_pointee()`](/mojo/stdlib/memory/unsafe_pointer/UnsafePointer#take_pointee)\n",
-    "function moves the pointee from the memory location pointed to by `ptr`. This is\n",
+    "method moves the pointee from the memory location pointed to by `ptr`. This is\n",
     "a consuming move—it invokes `__moveinit__()` on the destination value. It leaves\n",
     "the memory location uninitialized.\n",
     "\n",
     "The [`destroy_pointee()`](/mojo/stdlib/memory/unsafe_pointer/UnsafePointer#destroy_pointee)\n",
-    "function calls the destructor on the pointee, and leaves the memory location\n",
+    "method calls the destructor on the pointee, and leaves the memory location\n",
     "pointed to by `ptr` uninitialized. \n",
     "\n",
     "Both `take_pointee()` and `destroy_pointee()` require that the pointer is \n",
     "non-null, and the memory location contains a valid, initialized value of the \n",
     "pointee's type; otherwise the function results in undefined behavior.\n",
     "\n",
     "The [`move_pointee_into(self, dst)`](/mojo/stdlib/memory/unsafe_pointer/UnsafePointer#move_pointee_into)\n",
-    "function moves the pointee from one pointer location to another. Both pointers\n",
+    "method moves the pointee from one pointer location to another. Both pointers\n",
     "must be non-null. The source location must contain a valid, initialized value of \n",
     "the pointee's type, and is left uninitialized after the call. The destination \n",
     "location is assumed to be uninitialized—if it contains a valid value, that\n",