feat: rename Sequence.list method to toList and update all call sites

The `.list` method on Sequence was renamed to `.toList` to better reflect its
purpose of converting a sequence into a List object. This change updates the
method definition in `builtin/core.wren` and `src/vm/wren_core.c`, along with
all test files that called `.list` on sequences, maps, ranges, and custom
sequence implementations. The test file `test/core/sequence/list.wren` was also
renamed to `test/core/sequence/to_list.wren` to match the new method name.

test/core/sequence/to_list.wren

@@ -8,4 +8,4 @@ class TestSequence is Sequence {
   iteratorValue(iterator) { iterator }
 }
 
-IO.print((new TestSequence).list) // expect: [1, 2, 3]
+IO.print((new TestSequence).toList) // expect: [1, 2, 3]