fix: reword filter command-line option

Author: TimD1

src/globals.cpp

@@ -458,7 +458,7 @@ void Globals::print_usage() const
 
     printf("\n  Variant Filtering/Selection:\n");
     printf("  -f, --filter <STRING1,STRING2...> [ALL]\n");
-    printf("      select just variants passing these FILTERs (OR operation)\n");
+    printf("      select just variants with these FILTER values (OR operation)\n");
     printf("  -l, --largest-variant <INTEGER> [%d]\n", g.max_size);
     printf("      maximum variant size, larger variants ignored\n");
     printf("  -sv, --sv-threshold <INTEGER> [%d]\n", g.sv_threshold);

src/variant.cpp

@@ -688,7 +688,7 @@ variantData::variantData(std::string vcf_fn,
                 }
             }
 
-            // if so, save this filter's index
+            // if so, save this filter's index (to compare against for variants)
             if (filter_idx >= 0) {
                 for (int j = 0; j < hdr->hrec[i]->nkeys; j++) {
                     if (std::string(hdr->hrec[i]->keys[j]) == std::string("IDX")) {