patch 7.4.875

Problem:    Not obvious how to contribute.
Solution:   Add a remark about CONTRIBUTING.md to README.md

README.md

@@ -89,6 +89,11 @@ See one of these files for system-specific instructions:
 There are more `README_*.txt` files, depending on the distribution you used.
 
 
+## Contributing ##
+
+If you would like to help making Vim better, see the `CONTRIBUTING.md` file.
+
+
 ## Information ##
 
 The latest news about Vim can be found on the Vim home page:

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    875,
 /**/
     874,
 /**/