fix format and HTML problems with 1987/heckbert/index.html

1987/heckbert/README.md

@@ -36,10 +36,12 @@ Try not to
 [Fold, Spindle or Mutilate](https://repository.library.brown.edu/studio/item/bdr:788264/PDF/)
 files. :-)
 
-The judges used this program to fold up\
-very long lines which the BSD fold(1)\
-was unable to process. This program has\
-been added to the contest tool chest.
+```
+    The judges used this program to fold up
+    very long lines which the BSD fold(1)
+    was unable to process. This program has
+    been added to the contest tool chest.
+```
 
 
 ## Author's remarks: