Add a small separation between histogram and summary lines

Also add a warning in documentation about the summary statistics
being approximage, in case somebody tries to do the actual math
and finds it doesn't quite match up.

szutil_lagometer/README.md

@@ -11,4 +11,6 @@ Additionally, there are a couple of lines of statistics at the bottom, with:
 - `max_lag`: The engine's exponentially-averaged max lag statistic
 - `uptime`: How long the server has been running continuously
 
+Note that summary statistics (e.g. mean, quantiles, and especially max_lag) are approximate and based on pre-rounded or pre-aggregated statistics.
+
 Players will see the lagometer if they have the `lagometer` priv, and enable the lagometer toggle via the `/lagometer` command.  The meter displays on the bottom right of the screen.

szutil_lagometer/init.lua

@@ -48,6 +48,9 @@ local newperiod = loadstring("return {" .. string_rep("0,", bucket_max) .. "}")
 local padx = getconf("padx") or 8
 local pady = getconf("pady") or 24
 
+-- Separation between graph and summary
+local separate = getconf("separate") or 8
+
 ------------------------------------------------------------------------
 -- MEASUREMENT
 
@@ -159,7 +162,8 @@ local function updatehud(player)
 						text = text,
 						alignment = {x = -1, y = -1},
 						number = 0xC0C0C0,
-						offset = {x = -padx, y = -pady}
+						offset = {x = -padx, y = -pady + (line <= bucket_max
+								and -separate or 0)}
 					})
 			}
 		elseif mline and text == "" then