extenstion -> extension

src/dialog/SDL_dialog_utils.h

@@ -46,7 +46,7 @@ char *convert_filter(const SDL_DialogFileFilter filter, NameTransform ntf,
                      const char *suffix, const char *ext_prefix,
                      const char *ext_separator, const char *ext_suffix);
 
-// Converts the extenstion list of a filter into a single string.
+// Converts the extension list of a filter into a single string.
 // <prefix>[extension]{<separator>[extension]...}<suffix>
 char *convert_ext_list(const char *list, const char *prefix,
                        const char *separator, const char *suffix);