Sketch: infinite construction lines (#1359) (#1547)

Thanks @DuBearte.

assets/locales/zh.json

@@ -507,6 +507,7 @@
   "cmd.sketch_fit_curves_to_section": "将曲线拟合到网格截面",
   "cmd.sketch_glyphs": "约束符号",
   "cmd.sketch_include_3d": "包含三维几何",
+  "cmd.sketch_infinite": "无限长直线",
   "cmd.sketch_insert_dxf": "插入 DXF",
   "cmd.sketch_insert_svg": "插入 SVG",
   "cmd.sketch_inspect": "检查草图",
@@ -1139,6 +1140,7 @@
   "ui.homeView": "主视图",
   "ui.horizontal_vertical": "水平/垂直",
   "ui.import_ellipsis": "导入…",
+  "ui.infinite": "无限",
   "ui.insert": "插入",
   "ui.inspect": "检查",
   "ui.intersect": "相交",