feat: add Sequence.any method as complement to Sequence.all

Adds a new `any` method to the Sequence class that tests whether any element
in the sequence passes the given predicate function, returning true on the
first match or false if none match. Includes documentation, core library
source update, and three new test files covering basic functionality,
non-boolean return values, and non-function argument error handling.

builtin/core.wren

@@ -22,6 +22,13 @@ class Sequence {
     return true
   }
 
+  any(f) {
+    for (element in this) {
+      if (f.call(element)) return true
+    }
+    return false
+  }
+
   reduce(acc, f) {
     for (element in this) {
       acc = f.call(acc, element)