Comment typo fix

gas/write.c

@@ -123,7 +123,7 @@ void print_fixup (fixS *);
 /* We generally attach relocs to frag chains.  However, after we have
    chained these all together into a segment, any relocs we add after
    that must be attached to a segment.  This will include relocs added
-   in md_estimate_size_for_relax, for example.  */
+   in md_estimate_size_before_relax, for example.  */
 static bool frags_chained = false;
 
 static unsigned int n_fixups;