Renderer.toggleFold works for folded, foldable and non-foldable lines

When a line is not foldable, we search upward for a suggested fold that contains it and apply that fold instead. If called with a row that is already folded, it unfolds it.

src/app/keymaps/editor.coffee

@@ -27,7 +27,8 @@ window.keymap.bindKeys '.editor',
   'meta-z': 'undo'
   'meta-Z': 'redo'
   'alt-meta-w': 'toggle-soft-wrap'
-  'alt-meta-f': 'fold-selection'
+  'alt-meta-f': 'toggle-fold'
+  'alt-meta-ctrl-f': 'fold-selection'
   'alt-meta-u': 'unfold'
   'alt-meta-left': 'split-left'
   'alt-meta-right': 'split-right'

src/app/renderer.coffee

@@ -57,11 +57,18 @@ class Renderer
     if fold = @largestFoldForBufferRow(bufferRow)
       fold.destroy()
     else
-      @createFoldAtBufferRow(bufferRow)
+      rowToFold = bufferRow
+      while rowToFold >= 0
+        rowRange = @foldSuggester.rowRangeForFoldAtBufferRow(rowToFold)
+        if rowRange and (rowRange[0] - 1) <= bufferRow <= rowRange[1]
+          if fold = @largestFoldForBufferRow(rowRange[0])
+            fold.destroy()
+          else
+            @createFold(rowRange...)
 
-  createFoldAtBufferRow: (bufferRow) ->
-    [startRow, endRow] = @foldSuggester.rowRangeForFoldAtBufferRow(bufferRow)
-    @createFold(startRow, endRow)
+          return
+        else
+          rowToFold--
 
   createFold: (startRow, endRow) ->
     fold = new Fold(this, startRow, endRow)