Wording fix, "many data" is incorrect.

Noted by Piotr Sikora.

src/http/modules/ngx_http_proxy_module.c

diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
index a8bbff6..24fbc2f 100644
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -1560,7 +1560,7 @@
         p->upstream_done = 1;
 
         ngx_log_error(NGX_LOG_WARN, r->connection->log, 0,
-                      "upstream sent too many data");
+                      "upstream sent too much data");
     }
 
     return NGX_OK;