patch 8.2.3914: various spelling mistakes in comments

Problem:    Various spelling mistakes in comments.
Solution:   Fix the mistakes. (Dominique Pellé, closes #9416)
diff --git a/src/if_python3.c b/src/if_python3.c
index 4944ab8..db88527 100644
--- a/src/if_python3.c
+++ b/src/if_python3.c
@@ -766,7 +766,7 @@
 
 # if !(defined(PY_NO_RTLD_GLOBAL) && defined(PY3_NO_RTLD_GLOBAL)) && defined(UNIX) && defined(FEAT_PYTHON)
     // Can't have Python and Python3 loaded at the same time.
-    // It cause a crash, because RTLD_GLOBAL is needed for
+    // It causes a crash, because RTLD_GLOBAL is needed for
     // standard C extension libraries of one or both python versions.
     if (python_loaded())
     {