Added comments [skip ci]

src/hnsw.c

@@ -82,6 +82,7 @@ HnswInit(void)
 							 NULL, &hnsw_iterative_search,
 							 HNSW_ITERATIVE_SEARCH_OFF, hnsw_iterative_search_options, PGC_USERSET, 0, NULL, NULL, NULL);
 
+	/* This is approximate and does not apply to the initial scan */
 	DefineCustomIntVariable("hnsw.max_search_tuples", "Sets the max number of candidates to visit for iterative search",
 							"-1 means no limit", &hnsw_max_search_tuples,
 							-1, -1, INT_MAX, PGC_USERSET, 0, NULL, NULL, NULL);

src/ivfflat.c

@@ -45,6 +45,7 @@ IvfflatInit(void)
 							 NULL, &ivfflat_iterative_search,
 							 IVFFLAT_ITERATIVE_SEARCH_OFF, ivfflat_iterative_search_options, PGC_USERSET, 0, NULL, NULL, NULL);
 
+	/* If this is less than probes, probes is used */
 	DefineCustomIntVariable("ivfflat.max_probes", "Sets the max number of probes for iterative search",
 							"-1 means no limit", &ivfflat_max_probes,
 							-1, -1, IVFFLAT_MAX_LISTS, PGC_USERSET, 0, NULL, NULL, NULL);