Update README.md (#3543)

prettify

README.md

@@ -294,19 +294,19 @@ the structure definition.
 Another important Redis data structure is the one defining a client.
 In the past it was called `redisClient`, now just `client`. The structure
 has many fields, here we'll just show the main ones:
-
+```c
-    struct client {
+struct client {
-        int fd;
+    int fd;
-        sds querybuf;
+    sds querybuf;
-        int argc;
+    int argc;
-        robj **argv;
+    robj **argv;
-        redisDb *db;
+    redisDb *db;
-        int flags;
+    int flags;
-        list *reply;
+    list *reply;
-        char buf[PROTO_REPLY_CHUNK_BYTES];
+    char buf[PROTO_REPLY_CHUNK_BYTES];
-        ... many other fields ...
+    // ... many other fields ...
-    }
+}
-
+```
 The client structure defines a *connected client*:
 
 * The `fd` field is the client socket file descriptor.