Replaced "can not" with "cannot" and "could not" in a bunch of places.
Fixed nearby grammar errors.

src/http/ngx_http.c

diff --git a/src/http/ngx_http.c b/src/http/ngx_http.c
index 5ca9fed..e809045 100644
--- a/src/http/ngx_http.c
+++ b/src/http/ngx_http.c
@@ -1226,7 +1226,7 @@
 #endif
 
     /*
-     * we can not compare whole sockaddr struct's as kernel
+     * we cannot compare whole sockaddr struct's as kernel
      * may fill some fields in inherited sockaddr struct's
      */