Correct a typo in docstring

src/algebra/fops.spad

@@ -314,7 +314,7 @@ BasicKeyedAccessFile : Exports == Implementation where
     close! : % -> Void
       ++ close! closes the keyed access file.
     read : (%, String) -> None
-      ++ read(f, key) reads item with the key \pad{key} from \spad{f}.
+      ++ read(f, key) reads item with the key \spad{key} from \spad{f}.
     write! : (%, String, None) -> Void
       ++ write! writes one item to the keyed access file.
     remove! : (%, String) -> Void