doc: Update our requirements for changes file

Closes tpo/core/team#3.

Signed-off-by: David Goulet <dgoulet@torproject.org>

doc/HACKING/CodingStandards.md

@@ -87,6 +87,18 @@ months and expect it to merge cleanly. Try to merge pieces early and often.
 
 ## How we log changes
 
+Before diving in the details on how to write a changes file, note that we do
+NOT require a changes file for:
+
+  * Any change to a file that is not distributed in the tarball. This
+    includes:
+    - Any change to our CI configuration that does not affect the distributed
+      source.
+    - Any change to developer-only tools, unless those tools are distributed
+      in the tarball.
+  * Non-functional code movement.
+  * Identifier re-namings, comment edits, spelling fixes, and so on.
+
 When you do a commit that needs a ChangeLog entry, add a new file to
 the `changes` toplevel subdirectory.  It should have the format of a
 one-entry changelog section from the current ChangeLog file, as in