Add some missing credits.

@mysticjim and @Sundiata manage the community, but were not named in
those credits yet.
@Langbart does a lot of valuable work (amongst which is writing patches)
and was not credited at their first patch (my fault).

Differential revision: https://code.wildfiregames.com/D3880
This was SVN commit r25364.

binaries/data/mods/public/gui/credits/texts/community.json

@@ -19,11 +19,13 @@
 				{ "nick": "Kimball", "name": "Rob Kimball" },
 				{ "nick": "King Tutankhamun", "name": "Desmond Talkington" },
 				{ "nick": "MishFTW", "name": "A. Mishra" },
+				{ "nick": "mysticjim" },
 				{ "nick": "Morgan", "name": "Morgan Ramsay" },
 				{ "nick": "Red_08", "name": "Joshua Barker" },
 				{ "nick": "ricotz", "name": "Rico Tzschichholz" },
 				{ "nick": "Rodrigo", "name": "Klass Van Waesberghe" },
 				{ "nick": "Sam (aka Ph4ntom)", "name": "Sam Carlton" },
+				{ "nick": "Sundiata", "name": "Malcolm Kwadwo Kwarte Quartey" },
 				{ "nick": "Sunshine", "name": "Belle Green" },
 				{ "nick": "user1", "name": "A. C." },
 				{ "nick": "Yiuel", "name": "Ugo Lachapelle" }

binaries/data/mods/public/gui/credits/texts/programming.json

@@ -143,6 +143,7 @@
 				{ "nick": "kingbasil", "name": "Giannis Fafalios" },
 				{ "nick": "Krinkle", "name": "Timo Tijhof" },
 				{ "nick": "lafferjm", "name": "Justin Lafferty" },
+				{ "nick": "Langbart" },
 				{ "nick": "LeanderH", "name": "Leander Hemelhof" },
 				{ "nick": "leper", "name": "Georg Kilzer" },
 				{ "nick": "Link Mauve", "name": "Emmanuel Gil Peyrot" },