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.

1992/guidelines.txt

@@ -53,7 +53,7 @@ HINTS AND SUGGESTIONS:
     a number of tests to an entry:
 
 	* 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' lines
 	* C pre-process the source ignoring '#define' and '#include' lines
 	* run it through a C beautifier
@@ -143,7 +143,7 @@ OUR LIKES AND DISLIKES:
 	     (it is ok only if you warn us in the 'remark' header item)
 	* won't compile under both BSD or SYS V Un*x
 	* abusing the build file 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 identical to previous losers  :-)