Fix various typos in source documentation (#11553)

* Fix various typos in source documentation

* Delete cmake/modules/Catch2/CatchAddTests.cmake

* Delete tests/example/example_tests_main.cpp

* Revert test_config.cpp

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Co-authored-by: Ian Bassi <ian.bassi@outlook.com>

tests/libslic3r/test_indexed_triangle_set.cpp

@@ -225,7 +225,7 @@ TEST_CASE("Reduce one edge by Quadric Edge Collapse", "[its]")
                     Vec3f(0.9f, .1f, -.1f)};
     its.indices  = {Vec3i32(1, 0, 3), Vec3i32(2, 1, 3), Vec3i32(0, 2, 3),
                    Vec3i32(0, 1, 4), Vec3i32(1, 2, 4), Vec3i32(2, 0, 4)};
-    // edge to remove is between vertices 2 and 4 on trinagles 4 and 5
+    // edge to remove is between vertices 2 and 4 on triangles 4 and 5
 
     indexed_triangle_set its_ = its; // copy
     // its_write_obj(its, "tetrhedron_in.obj");