patch 8.2.3703: most people call F# "fsharp" and not "fs"

Problem:    Most people call F# "fsharp" and not "fs".
Solution:   Rename filetype "fs" to "fsharp".

src/testdir/test_filetype.vim

@@ -187,7 +187,7 @@ let s:filename_checks = {
     \ 'fpcmake': ['file.fpc'],
     \ 'framescript': ['file.fsl'],
     \ 'freebasic': ['file.fb', 'file.bi'],
-    \ 'fs': ['file.fs'],
+    \ 'fsharp': ['file.fs', 'file.fsi', 'file.fsx'],
     \ 'fstab': ['fstab', 'mtab'],
     \ 'fvwm': ['/.fvwm/file', 'any/.fvwm/file'],
     \ 'gdb': ['.gdbinit', 'gdbinit'],
@@ -977,7 +977,7 @@ func Test_fs_file()
 
   call writefile(['looks like F#'], 'Xfile.fs')
   split Xfile.fs
-  call assert_equal('fs', &filetype)
+  call assert_equal('fsharp', &filetype)
   bwipe!
 
   let g:filetype_fs = 'forth'

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3703,
 /**/
     3702,
 /**/