PL Warsaw Central specific semaphore (#676)

Recently, I've surveyed Warsaw Central with its new railway signalling
and having discussed at forum on Skyscrapercity
(https://www.skyscrapercity.com/threads/warszawa-warszawski-w%C4%99ze%C5%82-kolejowy.979536/page-364?post_id=195487518#post-195487518)
I've realised that a certain type of semaphore hadn't existed.

It's the case when semaphore has 5 cells
(green-yellow-red-yellow-white), but the 2-cell signals contain only
yellow lights, no green-yellow (as it's currently implied by code).
Thus, I've made it possible to render properly currently 2 semaphores
(G1C and G2C, https://www.openstreetmap.org/node/12021271222 and
https://www.openstreetmap.org/node respectively) at Warsaw Central
station

---------

Co-authored-by: Hidde Wieringa <[email protected]>

Author: Anasmasuris

features/signals_railway_signals.yaml

@@ -6684,6 +6684,10 @@ features:
           - { all: [ 'PL-PKP:s7', 'PL-PKP:s10a' ], value: 'pl/s6-10a-4' }
           - { all: [ 'PL-PKP:s6', 'PL-PKP:s11a' ], value: 'pl/s6-10a-4' }
           - { all: [ 'PL-PKP:s7', 'PL-PKP:s11a' ], value: 'pl/s6-10a-4' }
+          - { all: [ 'PL-PKP:s2', 'PL-PKP:s12' ], value: 'pl/s13-5' }
+          - { all: [ 'PL-PKP:s3', 'PL-PKP:s12' ], value: 'pl/s13-5' }
+          - { all: [ 'PL-PKP:s2', 'PL-PKP:s13' ], value: 'pl/s13-5' }
+          - { all: [ 'PL-PKP:s3', 'PL-PKP:s13' ], value: 'pl/s13-5' }
           - { any: [ 'PL-PKP:s6', 'PL-PKP:s7' ], value: 'pl/s6-4' }
           - { any: [ 'PL-PKP:s8', 'PL-PKP:s9' ], value: 'pl/s9-4' }
           - { any: [ 'PL-PKP:s10a', 'PL-PKP:s11a' ], value: 'pl/s10a-4' }