Properly free buffer entry

g_slist_delete_link() is not enough we also need to call _free_entry()
on the entry.

This fixes a memleak in win_insert_last_read_position_marker()

src/ui/buffer.c

@@ -114,6 +114,7 @@ buffer_remove_entry_by_id(ProfBuff buffer, const char *const id)
     while (entries) {
         ProfBuffEntry *entry = entries->data;
         if (entry->id && (g_strcmp0(entry->id, id) == 0)) {
+            _free_entry(entry);
             buffer->entries = g_slist_delete_link(buffer->entries, entries);
         }
         entries = g_slist_next(entries);