feat: add skipBlockComment parser with nesting support and three test cases

Implement a new skipBlockComment function in the compiler that handles nested /* */ block comments by tracking a nesting counter. The parser advances through comment characters, incrementing nesting on opening /* and decrementing on closing */. Also add three test files: comment_block.wren verifying inline and nested block comments, comment_block_at_eof.wren for a block comment at end of file without newline, and comment_line_at_eof.wren for a line comment at end of file without newline.

test/comment_block.wren

@@ -0,0 +1,5 @@
+// In middle of line.
+io.write/* ... */(/* */"ok"/* */) // expect: ok
+
+// Nested.
+io.write(/* in /* nest */ out */"ok") // expect: ok

test/comment_block_at_eof.wren

@@ -0,0 +1,2 @@
+io.write("ok") // expect: ok
+/* comment */

test/comment_line_at_eof.wren

@@ -0,0 +1,2 @@
+io.write("ok") // expect: ok
+// comment