Change 'tri-graphs' to 'trigraphs' - it's one word

The is a file excluded from this commit that has had the change because
there are other changes but the file is incomplete. That file will be
committed when the fixes are complete which will happen at a later date.

1991/rules.txt

@@ -195,7 +195,7 @@ POINTS TO PONDER:
     each entry is judged when we:
 
 	* look at the original source
-	* If it is ANSI, convert tri-graphs to ASCII
+	* If it is ANSI, convert trigraphs to ASCII
 	* C pre-process the source ignoring '#include' '#define' lines
 	* C pre-process the source ignoring '#define' and '#include' lines
 	* run it through a C beautifier
@@ -216,7 +216,7 @@ POINTS TO PONDER:
 	     (it is ok only if you warn us in the 'remark' header item)
 	* won't compile under both BSD or SYS V Un*x
 	* use an excessively long compile line to get around the size limit
-	* obfuscate by excessive use of ANSI tri-graphs
+	* obfuscate by excessive use of ANSI trigraphs
 	* are longer than they need to be
 	* are similar to previous winners
 	* are similar to previous losers  :-)