gh-61456: Add Thai language codec aliases (#15079)

Adding aliases for Thai language support. The current code page is an implementation of the windows code page.
This will alias '874', 'ms874', and 'windows_874' to cp874, adding Thai language support for those users.

Co-authored-by: Łukasz Langa <[email protected]>

Author: btwood

Lib/encodings/aliases.py

@@ -204,6 +204,11 @@
     'csibm869'           : 'cp869',
     'ibm869'             : 'cp869',
 
+    # cp874 codec
+    '874'                : 'cp874',
+    'ms874'              : 'cp874',
+    'windows_874'        : 'cp874',
+
     # cp932 codec
     '932'                : 'cp932',
     'ms932'              : 'cp932',

Misc/NEWS.d/next/Library/2019-08-05-13-58-10.bpo-17254.11xglZ.rst

@@ -0,0 +1 @@
+Added aliases for Thai Language using Microsoft Code Pages.