patch 9.1.1478: Unused assignment in ex_uniq()

Problem:  Unused assignment in ex_uniq() (after v9.1.1476)
Solution: Remove the assignment and the wrong comments above
          (zeertzjq).

closes: #17596

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index cd2c304..c4a86c9 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -729,15 +729,9 @@
 	}
     }
 
-    // Make an array with all line numbers.  This avoids having to copy all
-    // the lines into allocated memory.
-    // When remove deplicating on strings "start_col_nr" is the offset in the
-    // line, for numbers remove deplicating it's the number to uniq on.  This
-    // means the pattern matching only has to be done once per line.
-    // Also get the longest line length for allocating "sortbuf".
+    // Find the length of the longest line.
     for (lnum = eap->line1; lnum <= eap->line2; ++lnum)
     {
-	s = ml_get(lnum);
 	len = ml_get_len(lnum);
 	if (maxlen < len)
 	    maxlen = len;