Update README.md (#1381)

Minor textual cleanup.

plugin/cache/README.md

@@ -6,7 +6,7 @@
 
 ## Description
 
-With *cache* enabled all records except zone transfers and metadata records will be cached for up to
+With *cache* enabled, all records except zone transfers and metadata records will be cached for up to
 3600s. Caching is mostly useful in a scenario when fetching data from the backend (upstream,
 database, etc.) is expensive.
 
@@ -16,9 +16,9 @@ database, etc.) is expensive.
 cache [TTL] [ZONES...]
 ~~~
 
-* **TTL** max TTL in seconds. If not specified, the maximum TTL will be used which is 3600 for
+* **TTL** max TTL in seconds. If not specified, the maximum TTL will be used, which is 3600 for
     noerror responses and 1800 for denial of existence ones.
-    Setting a TTL of 300: `cache 300` would cache the record up to 300 seconds.
+    Setting a TTL of 300: `cache 300` would cache records up to 300 seconds.
 * **ZONES** zones it should cache for. If empty, the zones from the configuration block are used.
 
 Each element in the cache is cached according to its TTL (with **TTL** as the max).
@@ -36,13 +36,13 @@ cache [TTL] [ZONES...] {
 ~~~
 
 * **TTL**  and **ZONES** as above.
-* `success`, override the settings for caching successful responses, **CAPACITY** indicates the maximum
+* `success`, override the settings for caching successful responses. **CAPACITY** indicates the maximum
   number of packets we cache before we start evicting (*randomly*). **TTL** overrides the cache maximum TTL.
-* `denial`, override the settings for caching denial of existence responses, **CAPACITY** indicates the maximum
+* `denial`, override the settings for caching denial of existence responses. **CAPACITY** indicates the maximum
   number of packets we cache before we start evicting (LRU). **TTL** overrides the cache maximum TTL.
   There is a third category (`error`) but those responses are never cached.
-* `prefetch`, will prefetch popular items when they are about to be expunged from the cache.
-  Popular means **AMOUNT** queries have been seen no gaps of **DURATION** or more between them.
+* `prefetch` will prefetch popular items when they are about to be expunged from the cache.
+  Popular means **AMOUNT** queries have been seen with no gaps of **DURATION** or more between them.
   **DURATION** defaults to 1m. Prefetching will happen when the TTL drops below **PERCENTAGE**,
   which defaults to `10%`. Values should be in the range `[10%, 90%]`. Note the percent sign is
   mandatory. **PERCENTAGE** is treated as an `int`.