Add several spelling corrections (#717)

* Add several spelling corrections

* Add legth->length

codespell_lib/data/dictionary.txt

@@ -1726,6 +1726,8 @@ bizzare->bizarre
 blaim->blame
 blaimed->blamed
 blak->black, blank,
+blanck->blank, black,
+blancked->blanked
 blcok->block
 blcoks->blocks
 blessure->blessing
@@ -7748,6 +7750,7 @@ legitamate->legitimate
 legitimiately->legitimately
 legitmate->legitimate
 legnth->length
+legth->length
 leibnitz->leibniz
 leightweight->lightweight
 lenggth->length
@@ -8077,6 +8080,7 @@ matchs->matches
 matcing->matching
 mateiral->material
 mateirals->materials
+matemathical->mathematical
 mater->matter, master, mother, mater,
 materaial->material
 materaials->materials
@@ -13005,6 +13009,7 @@ thst->that
 tht->the, that,
 thta->that
 thte->the, that,
+thumbbnail->thumbnail
 thurver->further
 thyat->that
 tiem->time, item,