patch 8.2.4064: foam files are not detected

Problem:    Foam files are not detected.
Solution:   Detect the foam filetype by the path and file contents. (Mohammed
            Elwardi Fadeli, closes #9501)

runtime/autoload/dist/ft.vim

@@ -829,6 +829,23 @@ func dist#ft#Dep3patch()
   endfor
 endfunc
 
+" This function checks the first 15 lines for appearance of 'FoamFile'
+" and then 'object' in a following line.
+" In that case, it's probably an OpenFOAM file
+func dist#ft#FTfoam()
+    let ffile = 0
+    let lnum = 1
+    while lnum <= 15
+      if getline(lnum) =~# '^FoamFile'
+	let ffile = 1
+      elseif ffile == 1 && getline(lnum) =~# '^\s*object'
+	setf foam
+	return
+      endif
+      let lnum = lnum + 1
+    endwhile
+endfunc
+
 " Restore 'cpoptions'
 let &cpo = s:cpo_save
 unlet s:cpo_save