Fix typos with codespell

Using codespell 1.15.0.

Method:
```
$ cat > ../godot-word-whitelist.txt << EOF
ang
curvelinear
doubleclick
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
```

editor/editor_file_system.cpp

@@ -218,7 +218,7 @@ void EditorFileSystem::_scan_filesystem() {
 				if (first_scan) {
 					// only use this on first scan, afterwards it gets ignored
 					// this is so on first reimport we synchronize versions, then
-					// we dont care until editor restart. This is for usability mainly so
+					// we don't care until editor restart. This is for usability mainly so
 					// your workflow is not killed after changing a setting by forceful reimporting
 					// everything there is.
 					filesystem_settings_version_for_import = l.strip_edges();