patch 8.2.4187: gnuplot file not recognized

Problem:    Gnuplot file not recognized.
Solution:   Recognize ".gnuplot". (closes #9588)
diff --git a/src/testdir/test_filetype.vim b/src/testdir/test_filetype.vim
index ff2af5f..fb1aa63 100644
--- a/src/testdir/test_filetype.vim
+++ b/src/testdir/test_filetype.vim
@@ -203,7 +203,7 @@
     \ 'gitsendemail': ['.gitsendemail.msg.xxxxxx'],
     \ 'gkrellmrc': ['gkrellmrc', 'gkrellmrc_x'],
     \ 'gnash': ['gnashrc', '.gnashrc', 'gnashpluginrc', '.gnashpluginrc'],
-    \ 'gnuplot': ['file.gpi'],
+    \ 'gnuplot': ['file.gpi', '.gnuplot'],
     \ 'go': ['file.go'],
     \ 'gomod': ['go.mod'],
     \ 'gp': ['file.gp', '.gprc'],
diff --git a/src/version.c b/src/version.c
index 8e659e0..1d5160f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4187,
+/**/
     4186,
 /**/
     4185,