patch 8.2.4464: Dtrace files are recognized as filetype D

Problem:    Dtrace files are recognized as filetype D.
Solution:   Add a pattern for Dtrace files. (Teubel György, closes #9841)
            Add some more testing.
diff --git a/src/testdir/test_filetype.vim b/src/testdir/test_filetype.vim
index 01978ef..9614f55 100644
--- a/src/testdir/test_filetype.vim
+++ b/src/testdir/test_filetype.vim
@@ -132,6 +132,7 @@
     \ 'cvs': ['cvs123'],
     \ 'cvsrc': ['.cvsrc'],
     \ 'cynpp': ['file.cyn'],
+    \ 'd': ['file.d'],
     \ 'dart': ['file.dart', 'file.drt'],
     \ 'datascript': ['file.ds'],
     \ 'dcd': ['file.dcd'],
@@ -154,6 +155,7 @@
     \ 'dot': ['file.dot', 'file.gv'],
     \ 'dracula': ['file.drac', 'file.drc', 'filelvs', 'filelpe', 'drac.file', 'lpe', 'lvs', 'some-lpe', 'some-lvs'],
     \ 'dtd': ['file.dtd'],
+    \ 'dtrace': ['/usr/lib/dtrace/io.d'],
     \ 'dts': ['file.dts', 'file.dtsi'],
     \ 'dune': ['jbuild', 'dune', 'dune-project', 'dune-workspace'],
     \ 'dylan': ['file.dylan'],
@@ -827,6 +829,42 @@
   filetype off
 endfunc
 
+func Test_d_file()
+  filetype on
+
+  call writefile(['looks like D'], 'Xfile.d')
+  split Xfile.d
+  call assert_equal('d', &filetype)
+  bwipe!
+
+  call writefile(['#!/some/bin/dtrace'], 'Xfile.d')
+  split Xfile.d
+  call assert_equal('dtrace', &filetype)
+  bwipe!
+
+  call writefile(['#pragma  D  option'], 'Xfile.d')
+  split Xfile.d
+  call assert_equal('dtrace', &filetype)
+  bwipe!
+
+  call writefile([':some:thing:'], 'Xfile.d')
+  split Xfile.d
+  call assert_equal('dtrace', &filetype)
+  bwipe!
+
+  call writefile(['module this', '#pragma  D  option'], 'Xfile.d')
+  split Xfile.d
+  call assert_equal('d', &filetype)
+  bwipe!
+
+  call writefile(['import that', '#pragma  D  option'], 'Xfile.d')
+  split Xfile.d
+  call assert_equal('d', &filetype)
+  bwipe!
+
+  filetype off
+endfunc
+
 func Test_dep3patch_file()
   filetype on
 
diff --git a/src/version.c b/src/version.c
index 1491e81..69be8cd 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4464,
+/**/
     4463,
 /**/
     4462,