Docbot request is ignored if there are three dashes before it

[Totktonada]

See an example:

$ git log -p -1 | cat
commit 48ab9edfe904ca9ed758cae5144b61257e7e2777
Author: Alexander Turenko <alexander.turenko@tarantool.org>
Date:   Mon Apr 25 22:49:01 2022 +0300

    foo: bar bar bar
    
    Let's show an example:
    
    ```lua
    tarantool> 42
    ---
    - 42
    ...
    ```
    
    NO_TEST=moo power
    NO_CHANGELOG=moo power
    
    @TarantoolBot document
    Title: Now 42 is 42
    
    And it's amazing!

diff --git a/README.md b/README.md
index 03eb417f1..d4ee57413 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,8 @@
 [Tarantool][tarantool-url] is an in-memory computing platform consisting of a
 database and an application server.
 
+Moo power?
+
 It is distributed under [BSD 2-Clause][license] terms.
 
 Key features of the application server:

Run checkpatch:

$ /path/to/checkpatch/checkpatch.pl --color=always --git HEAD~1..HEAD
ERROR: Please add doc or NO_DOC=<reason> tag
ERROR: Please add changelog or NO_CHANGELOG=<reason> tag
ERROR: Please add test or NO_TEST=<reason> tag
total: 3 errors, 8 lines checked

Commit 48ab9edfe904 ("foo: bar bar bar") has style problems, please review.

NOTE: If any of the errors are false positives, please file a bug at
      https://github.com/tarantool/checkpatch/issues

Also it seems that the Moo power does not work for NO_TEST and NO_CHANGELOG in the case.