Use binary literals in the secret-handshake example (#893)

* Use binary literals in the secret-handshake example

The exercise's instructions give the gesture values in binary:

    00001 = wink
    00010 = double blink
    00100 = close your eyes
    01000 = jump
    10000 = Reverse the order of the operations in the secret handshake.

while the example gave them in decimal, so reading the two side by side
meant converting between representations.

Binary literals need Scala 3.5 or later, which the track only got in #888
(3.9.0 LTS). This is the readability improvement #882 asked for, and the
track's first use of the syntax.

allergies was considered and deliberately left alone: its instructions
list the allergen values in decimal, so the same change would make its
example diverge from its spec rather than match it. variable-length-quantity
already names its masks (0x7f, 0x80) and reads fine as it is.

Verified with `bin/test secret-handshake` (11 tests) and
`bin/verify-exercises-in-docker secret-handshake` against the published
test runner image.

Fixes #892

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* Add rabestro to the secret-handshake contributors

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

---------

Co-authored-by: Jegors Cemisovs <jcemisovs@evolution.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Author: 3 people

exercises/practice/secret-handshake/.meta/Example.scala

@@ -1,7 +1,7 @@
 object SecretHandshake {
-  private val reverseGestures = 16
-  private def gestures = List((1, "wink"), (2, "double blink"),
-    (4, "close your eyes"), (8, "jump"))
+  private val reverseGestures = 0b10000
+  private def gestures = List((0b00001, "wink"), (0b00010, "double blink"),
+    (0b00100, "close your eyes"), (0b01000, "jump"))
 
   def commands(s: String): List[String] = {
     def isValid = s.count(c => c != '0' && c != '1') == 0

exercises/practice/secret-handshake/.meta/config.json

@@ -5,6 +5,7 @@
   "contributors": [
     "ErikSchierboom",
     "ppartarr",
+    "rabestro",
     "rajeshpg"
   ],
   "files": {