patch 8.2.3686: filetype detection often mixes up Forth and F#

Problem:    Filetype detection often mixes up Forth and F#.
Solution:   Add a function to inspect the file contents. (Doug Kearns)
diff --git a/runtime/doc/filetype.txt b/runtime/doc/filetype.txt
index 38622a4..8cb2e11 100644
--- a/runtime/doc/filetype.txt
+++ b/runtime/doc/filetype.txt
@@ -139,18 +139,19 @@
 
 	file name	variable ~
 	*.asa		g:filetype_asa	|ft-aspvbs-syntax| |ft-aspperl-syntax|
-	*.asp		g:filetype_asp	|ft-aspvbs-syntax| |ft-aspperl-syntax|
 	*.asm		g:asmsyntax	|ft-asm-syntax|
-	*.prg		g:filetype_prg
-	*.pl		g:filetype_pl
-	*.inc		g:filetype_inc
-	*.w		g:filetype_w	|ft-cweb-syntax|
+	*.asp		g:filetype_asp	|ft-aspvbs-syntax| |ft-aspperl-syntax|
+	*.fs		g:filetype_fs   |ft-forth-syntax|
 	*.i		g:filetype_i	|ft-progress-syntax|
+	*.inc		g:filetype_inc
 	*.m		g:filetype_m	|ft-mathematica-syntax|
 	*.p		g:filetype_p	|ft-pascal-syntax|
+	*.pl		g:filetype_pl
 	*.pp		g:filetype_pp	|ft-pascal-syntax|
+	*.prg		g:filetype_prg
 	*.sh		g:bash_is_sh	|ft-sh-syntax|
 	*.tex		g:tex_flavor	|ft-tex-plugin|
+	*.w		g:filetype_w	|ft-cweb-syntax|
 
 							*filetype-ignore*
 To avoid that certain files are being inspected, the g:ft_ignore_pat variable
@@ -538,6 +539,14 @@
 For further discussion of fortran_have_tabs and the method used for the
 detection of source format see |ft-fortran-syntax|.
 
+GPROF							*ft-gprof-plugin*
+
+The gprof filetype plugin defines a mapping <C-]> to jump from a function
+entry in the gprof flat profile or from a function entry in the call graph
+to the details of that function in the call graph.
+
+The mapping can be disabled with: >
+	let g:no_gprof_maps = 1
 
 GIT COMMIT                                              *ft-gitcommit-plugin*
 
diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index 08d3f5f..3bc5cf4 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -1533,6 +1533,14 @@
 conditionals are LightBlue for better distinction.
 
 
+FORTH						*forth.vim* *ft-forth-syntax*
+
+Files matching "*.fs" could be F# or Forth.  If the automatic detection
+doesn't work for you, or you don't edit F# at all, use this in your
+startup vimrc: >
+   :let filetype_fs = "forth"
+
+
 FORTRAN					*fortran.vim* *ft-fortran-syntax*
 
 Default highlighting and dialect ~