Fix typos with codespell

Using codespell 2.0.0.

Method:
```
$ cat > ../godot-word-whitelist.txt << EOF
ang
curvelinear
dof
doubleclick
fave
findn
GIRD
leapyear
lod
merchantibility
nd
numer
ois
ony
que
seeked
synching
te
uint
unselect
webp
EOF

$ codespell -w -q 3 -I ../godot-word-whitelist.txt --skip="./thirdparty,*.po"
$ git diff // undo unwanted changes
```

(cherry picked from commit eb78f80f03)

servers/physics/collision_solver_sat.cpp

@@ -703,7 +703,7 @@ public:
 		Vector3 axis = (p_point_B - p_point_A);
 		real_t depth = axis.length();
 
-		// Filter out bogus directions with a treshold and re-testing axis.
+		// Filter out bogus directions with a threshold and re-testing axis.
 		if (separator->best_depth - depth > 0.001) {
 			separator->test_axis(axis / depth);
 		}