many of our test plots have been bitten by #383 (#838)

since we adopted font-variant="tabular-nums" the left margin is too small for five-digits numbers

Author: Fil

test/output/athletesWeightCumulative.svg

@@ -4,6 +4,7 @@ import * as d3 from "d3";
 export default async function() {
   const athletes = await d3.csv("data/athletes.csv", d3.autoType);
   return Plot.plot({
+    marginLeft: 44,
     marks: [
       Plot.rectY(athletes, Plot.binX({y: "count"}, {x: "weight", cumulative: true}))
     ]

test/output/carsParcoords.svg

@@ -23,7 +23,7 @@ export default async function() {
   const xy = Plot.normalizeX("extent", {x: "value", y: "dimension", z: "dimension"});
 
   return Plot.plot({
-    marginLeft: 100,
+    marginLeft: 104,
     marginRight: 20,
     x: {
       axis: null

test/output/diamondsCaratPrice.svg

@@ -6,6 +6,7 @@ export default async function() {
   return Plot.plot({
     height: 640,
     grid: true,
+    marginLeft: 44,
     x: {
       label: "Carats →"
     },