Update index.js

Co-authored-by: David Chambers <dc@davidchambers.me>

Author: futpib

index.js

@@ -2385,7 +2385,7 @@
   //# fromEither :: Either a a -> a
   //.
   //. Takes an Either with the same type on the Left and on the Right
-  //. and return whichever value exists.
+  //. and returns whichever value exists.
   //.
   //. The inverse of [`tagBy`](#tagBy).
   //.