patch 8.2.1779: some debian changelog files are not recognized

Problem:    Some debian changelog files are not recognized.
Solution:   Add */debian/changelog. (Jason Franklin)

src/testdir/test_filetype.vim

@@ -128,6 +128,7 @@ let s:filename_checks = {
     \ 'dart': ['file.dart', 'file.drt'],
     \ 'datascript': ['file.ds'],
     \ 'dcd': ['file.dcd'],
+    \ 'debchangelog': ['changelog.Debian', 'changelog.dch', 'NEWS.Debian', 'NEWS.dch', '/debian/changelog'],
     \ 'debcontrol': ['/debian/control'],
     \ 'debsources': ['/etc/apt/sources.list', '/etc/apt/sources.list.d/file.list'],
     \ 'def': ['file.def'],

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1779,
 /**/
     1778,
 /**/