console.lua: allow scrolling up the log until only one line remains

Currently, if some log lines have very long text that actually
renders across multiple lines, even if you scroll to the top,
the topmost content will be pushed out of the screen by these
lines and will never be visible.

In STATS page 2/4/5/0, you can scroll down until there is one
line left on the screen, we can keep the scrolling behavior of
the log consistent with it.

player/lua/console.lua

@@ -761,9 +761,10 @@ local function render()
 
     local log_ass = ""
     local log_buffer = log_buffers[id] or {}
-    log_offset = math.max(math.min(log_offset, #log_buffer - max_lines), 0)
-    for i = #log_buffer - math.min(max_lines, #log_buffer) - log_offset + 1,
-            #log_buffer - log_offset do
+    log_offset = math.max(math.min(log_offset, #log_buffer - 1), 0)
+    local last = #log_buffer - log_offset
+    local first = math.max(last - math.min(max_lines, #log_buffer) + 1, 1)
+    for i = first, last do
         log_ass = log_ass .. style .. log_buffer[i].style ..
                   ass_escape(log_buffer[i].text) .. "\\N"
     end