stl2gts: add page (#5969)

pages/common/stl2gts.md

@@ -0,0 +1,24 @@
+# stl2gts
+
+> Convert STL files into the GTS (GNU triangulated surface library) file format.
+> More information: <https://manned.org/stl2gts>.
+
+- Convert an STL file to a GTS file:
+
+`stl2gts < {{path/to/file.stl}} > {{path/to/file.gts}}`
+
+- Convert an STL file to a GTS file and revert face normals:
+
+`stl2gts --revert < {{path/to/file.stl}} > {{path/to/file.gts}}`
+
+- Convert an STL file to a GTS file and do not merge vertices:
+
+`stl2gts --nomerge < {{path/to/file.stl}} > {{path/to/file.gts}}`
+
+- Convert an STL file to a GTS file and display surface statistics:
+
+`stl2gts --verbose < {{path/to/file.stl}} > {{path/to/file.gts}}`
+
+- Print help for `stl2gts`:
+
+`stl2gts --help`