Revert "Update L.Util.formatNum rounding" (Leaflet#6670)

* Revert "Update L.Util.formatNum rounding (Leaflet#6587)"

This reverts commit cd096d7.

* revert docs changes

spec/suites/core/UtilSpec.js

@@ -86,9 +86,6 @@ describe('Util', function () {
 			expect(L.Util.formatNum(13.12325555, 3)).to.eql(13.123);
 			expect(L.Util.formatNum(13.12325555)).to.eql(13.123256);
 			expect(L.Util.formatNum(13.12325555, 0)).to.eql(13);
-			expect(L.Util.formatNum(1.005, 2)).to.eql(1.01);
-			expect(L.Util.formatNum(1.555, 2)).to.eql(1.56);
-			expect(L.Util.formatNum(-1.4837191022531273, 18)).to.eql(-1.4837191022531273);
 		});
 	});
 

spec/suites/layer/GeoJSONSpec.js

@@ -80,12 +80,6 @@ describe("L.Marker#toGeoJSON", function () {
 			type: 'Point',
 			coordinates: [20.123, 10.123, 30.123]
 		});
-
-		marker = new L.Marker({lng: -1.4837191022531273, lat: 43.49222084042808});
-		expect(marker.toGeoJSON(18).geometry).to.eql({
-			type: 'Point',
-			coordinates: [-1.4837191022531273, 43.49222084042808]
-		});
 	});
 });
 

src/core/Util.js

@@ -114,8 +114,8 @@ export function falseFn() { return false; }
 // @function formatNum(num: Number, digits?: Number): Number
 // Returns the number `num` rounded to `digits` decimals, or to 6 decimals by default.
 export function formatNum(num, digits) {
-	digits = (digits === undefined ? 6 : digits);
-	return +(Math.round(num + ('e+' + digits)) + ('e-' + digits));
+	var pow = Math.pow(10, (digits === undefined ? 6 : digits));
+	return Math.round(num * pow) / pow;
 }
 
 // @function trim(str: String): String