patch 8.2.3087: Gemtext files are not recognized

Problem:    Gemtext files are not recognized.
Solution:   Recognize .gmi and .gemini files. (closes #8427)

runtime/filetype.vim

@@ -650,6 +650,9 @@ au BufNewFile,BufRead *.mo,*.gdmo		setf gdmo
 " Gedcom
 au BufNewFile,BufRead *.ged,lltxxxxx.txt	setf gedcom
 
+" Gemtext
+au BufNewFile,BufRead *.gmi,*.gemini		setf gemtext
+
 " Gift (Moodle)
 autocmd BufRead,BufNewFile *.gift		setf gift
 

src/testdir/test_filetype.vim

@@ -192,6 +192,7 @@ let s:filename_checks = {
     \ 'gdb': ['.gdbinit'],
     \ 'gdmo': ['file.mo', 'file.gdmo'],
     \ 'gedcom': ['file.ged', 'lltxxxxx.txt', '/tmp/lltmp', '/tmp/lltmp-file', 'any/tmp/lltmp', 'any/tmp/lltmp-file'],
+    \ 'gemtext': ['file.gmi', 'file.gemini'],
     \ 'gift': ['file.gift'],
     \ 'gitcommit': ['COMMIT_EDITMSG', 'MERGE_MSG', 'TAG_EDITMSG'],
     \ 'gitconfig': ['file.git/config', '.gitconfig', '.gitmodules', 'file.git/modules//config', '/.config/git/config', '/etc/gitconfig', '/etc/gitconfig.d/file', '/.gitconfig.d/file', 'any/.config/git/config', 'any/.gitconfig.d/file', 'some.git/config', 'some.git/modules/any/config'],

src/version.c

@@ -755,6 +755,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3087,
 /**/
     3086,
 /**/