Missing NUMBERTEXT_EXTENSION_SHA256SUM

...after faef35d8 "Move file download
verification from md5sum to sha256sum".

ATTENTION: A proper SHA from the source of that
b7cae45ad2c23551fd6ccb8ae2c1f59e-numbertext_0.9.5.oxt is needed. The value
substituted for now is just my local sha256sum after download.

Change-Id: Id31508f10c6cd936e5c6318731ceed71bdc25f48

download.lst

@@ -235,4 +235,5 @@ export ZLIB_TARBALL := zlib-1.2.11.tar.xz
 export ZMF_SHA256SUM := b69f7f6e94cf695c4b672ca65def4825490a1e7dee34c2126309b96d21a19e6b
 export ZMF_TARBALL := libzmf-0.0.1.tar.bz2
 
+NUMBERTEXT_EXTENSION_SHA256SUM := 1568ed1d2feb8210bb5de61d69574a165cded536cfa17c6953c9064076469de2
 UNOWINREG_SHA256SUM := eafde646a7dbe46d20c291685b0beac2382174d78d66ee990e229a1bf6e6cec6