docs: Apply remark

Co-authored-by: Thales Macedo Garitezi <thalesmg@gmail.com>

apps/emqx_dashboard/etc/emqx_dashboard.conf

@@ -5,7 +5,7 @@
 dashboard {
     default_username = "admin"
     default_password = "public"
-    ## Note: sample_interval should be divisible by 60.
+    ## Note: sample_interval should be a divisor of 60.
     ## like 1s, 2s, 3s, 5s, 10s, 12s, 15s, 20s, 30s, 60s
     sample_interval = 10s
     ## JWT token expiration time.