patch 9.1.0196: filetype: support for gnuplot files is lacking

Problem:  filetype: support for gnuplot files is lacking
Solution: Also detect *.gnuplot files
          (RobbiZ98)

closes: #14243

Signed-off-by: RobbiZ98 <113035863+RobbiZ98@users.noreply.github.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/filetype.vim

@@ -862,7 +862,7 @@ au BufNewFile,BufRead *.gts			setf typescript.glimmer
 au BufNewFile,BufRead *.gjs			setf javascript.glimmer
 
 " Gnuplot scripts
-au BufNewFile,BufRead *.gpi,.gnuplot		setf gnuplot
+au BufNewFile,BufRead *.gpi,*.gnuplot		setf gnuplot
 
 " Go (Google)
 au BufNewFile,BufRead *.go			setf go

src/testdir/test_filetype.vim

@@ -283,7 +283,7 @@ def s:GetFilenameChecks(): dict<list<string>>
     glsl: ['file.glsl'],
     gn: ['file.gn', 'file.gni'],
     gnash: ['gnashrc', '.gnashrc', 'gnashpluginrc', '.gnashpluginrc'],
-    gnuplot: ['file.gpi', '.gnuplot'],
+    gnuplot: ['file.gpi', '.gnuplot', 'file.gnuplot'],
     go: ['file.go'],
     gomod: ['go.mod'],
     gosum: ['go.sum', 'go.work.sum'],

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    196,
 /**/
     195,
 /**/