Replaced "can not" with "cannot" and "could not" in a bunch of places.
Fixed nearby grammar errors.
diff --git a/src/http/modules/ngx_http_dav_module.c b/src/http/modules/ngx_http_dav_module.c
index 0761c16..3bd9d3e 100644
--- a/src/http/modules/ngx_http_dav_module.c
+++ b/src/http/modules/ngx_http_dav_module.c
@@ -158,7 +158,7 @@
 
         if (r->uri.data[r->uri.len - 1] == '/') {
             ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
-                          "can not PUT to a collection");
+                          "cannot PUT to a collection");
             return NGX_HTTP_CONFLICT;
         }