fs: fix accidental C code in comment

Thanks to https://github.com/likeazir for spotting this

Change-Id: I0952482886cfadb23c723d89a64fd4ced1b57c92

fs/api.go

@@ -9,7 +9,7 @@
 // To create a file system, you should first define types for the
 // nodes of the file system tree.
 //
-//	struct myNode {
+//	type myNode struct {
 //	   fs.Inode
 //	}
 //