Cleanup: spelling in comments

source/blender/python/mathutils/mathutils.c

@@ -666,7 +666,7 @@ PyMODINIT_FUNC PyInit_mathutils(void)
   PyDict_SetItem(sys_modules, PyModule_GetNameObject(submodule), submodule);
 
   PyModule_AddObject(mod, "interpolate", (submodule = PyInit_mathutils_interpolate()));
-  /* XXX, python doesnt do imports with this usefully yet
+  /* XXX, python doesn't do imports with this usefully yet
    * 'from mathutils.geometry import PolyFill'
    * ...fails without this. */
   PyDict_SetItem(sys_modules, PyModule_GetNameObject(submodule), submodule);

source/blender/python/mathutils/mathutils_Quaternion.c

@@ -911,7 +911,7 @@ static PyObject *Quaternion_mul(PyObject *q1, PyObject *q2)
   return NULL;
 }
 /*------------------------obj *= obj------------------------------
- * inplace multiplication */
+ * in-place multiplication */
 static PyObject *Quaternion_imul(PyObject *q1, PyObject *q2)
 {
   float scalar;

source/blender/python/mathutils/mathutils_bvhtree.c

@@ -61,7 +61,7 @@
 #include "BLI_strict_flags.h"
 
 /* -------------------------------------------------------------------- */
-/** \name Docstring (snippets)
+/** \name Documentation String (snippets)
  * \{ */
 
 #define PYBVH_FIND_GENERIC_DISTANCE_DOC \

source/blender/python/mathutils/mathutils_geometry.c

@@ -193,7 +193,7 @@ static PyObject *M_Geometry_intersect_line_line(PyObject *UNUSED(self), PyObject
   }
 
   result = isect_line_line_v3(UNPACK4(lines), i1, i2);
-  /* The return-code isnt exposed,
+  /* The return-code isn't exposed,
    * this way we can check know how close the lines are. */
   if (result == 1) {
     closest_to_line_v3(i2, i1, lines[2], lines[3]);