style(error_log): apply PR suggestion

Co-authored-by: Chrono <chrono_cpp@me.com>

README.md

@@ -143,12 +143,12 @@ you will always get the value where your Lua code runs in but not others.
 
 lua\_kong\_error\_log\_append
 -------------------------------------------
-**syntax:** *lua_kong_error_log_append expression;*
+**syntax:** *lua_kong_error_log_append value;*
 
 **context:** *http* *server* *location*
 
 Append information to the standard error log format.
-Expression can contain text, variables and their combination.
+Value can contain text, variables and their combination.
 
 For example, with this configuration:
 ```

src/ngx_http_lua_kong_log_handler.c

@@ -36,7 +36,7 @@ ngx_http_lua_kong_error_handler(ngx_http_request_t *r, u_char **buf, size_t *len
         return;
     }
 
-    if (log_append_str.len ) {
+    if (log_append_str.len) {
 
        p = ngx_snprintf(*buf, len, ", %V", &log_append_str);
        len -= p - *buf;