patch 9.0.1438: .fs files are falsely recognized as forth files

Problem:    .fs files are falsely recognized as forth files.
Solution:   Check 100 lines for something that looks like forth. (Johan
            Kotlinski, closes #12219, closes #11988)

runtime/autoload/dist/ft.vim

@@ -307,14 +307,16 @@ export def FTfs()
   if exists("g:filetype_fs")
     exe "setf " .. g:filetype_fs
   else
-    var line = getline(nextnonblank(1))
+    var n = 1
-    # comments and colon definitions
+    while n < 100 && n <= line("$")
-    if line =~ '^\s*\.\=( ' || line =~ '^\s*\\G\= ' || line =~ '^\\$'
+      # Forth comments and colon definitions
-	  \ || line =~ '^\s*: \S'
+      if getline(n) =~ "^[:(\\\\] "
         setf forth
-    else
+        return
-      setf fsharp
       endif
+      n += 1
+    endwhile
+    setf fsharp
   endif
 enddef
 

src/testdir/test_filetype.vim

@@ -1212,27 +1212,11 @@ func Test_fs_file()
   call assert_equal('forth', &filetype)
   bwipe!
 
-  call writefile(['.( Forth displayed inline comment )'], 'Xfile.fs')
-  split Xfile.fs
-  call assert_equal('forth', &filetype)
-  bwipe!
-
   call writefile(['\ Forth line comment'], 'Xfile.fs')
   split Xfile.fs
   call assert_equal('forth', &filetype)
   bwipe!
 
-  " empty line comment - no space required
-  call writefile(['\'], 'Xfile.fs')
-  split Xfile.fs
-  call assert_equal('forth', &filetype)
-  bwipe!
-
-  call writefile(['\G Forth documentation comment '], 'Xfile.fs')
-  split Xfile.fs
-  call assert_equal('forth', &filetype)
-  bwipe!
-
   call writefile([': squared ( n -- n^2 )', 'dup * ;'], 'Xfile.fs')
   split Xfile.fs
   call assert_equal('forth', &filetype)

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1438,
 /**/
     1437,
 /**/