Fix typos with codespell

Using codespell 2.2-dev from current git.

Added `misc/scripts/codespell.sh` to make it easier to run it once in a
while and update the skip and ignore lists.

(cherry picked from commit 1bdb82c64e)

main/tests/test_math.cpp

@@ -319,7 +319,7 @@ public:
 						curly_stack++;
 						break;
 					} else {
-						break; //whathever else
+						break; //whatever else
 					}
 				}