allow adding whole diff to patch

this was causing a panic

add integration test for toggling all commit files

docs/keybindings/Keybindings_en.md

@@ -123,6 +123,7 @@ _This file is auto-generated. To update, make the changes in the pkg/i18n direct
   <kbd>o</kbd>: open file
   <kbd>e</kbd>: edit file
   <kbd>space</kbd>: toggle file included in patch
+  <kbd>a</kbd>: toggle all files included in patch
   <kbd>enter</kbd>: enter file to add selected lines to the patch (or toggle directory collapsed)
   <kbd>`</kbd>: toggle file tree view
 </pre>

docs/keybindings/Keybindings_nl.md

@@ -123,6 +123,7 @@ _This file is auto-generated. To update, make the changes in the pkg/i18n direct
   <kbd>o</kbd>: open bestand
   <kbd>e</kbd>: verander bestand
   <kbd>space</kbd>: toggle bestand inbegrepen in patch
+  <kbd>a</kbd>: toggle all files included in patch
   <kbd>enter</kbd>: enter bestand om geselecteerde regels toe te voegen aan de patch
   <kbd>`</kbd>: toggle bestandsboom weergave
 </pre>

docs/keybindings/Keybindings_pl.md

@@ -123,6 +123,7 @@ _This file is auto-generated. To update, make the changes in the pkg/i18n direct
   <kbd>o</kbd>: otwórz plik
   <kbd>e</kbd>: edytuj plik
   <kbd>space</kbd>: toggle file included in patch
+  <kbd>a</kbd>: toggle all files included in patch
   <kbd>enter</kbd>: enter file to add selected lines to the patch (or toggle directory collapsed)
   <kbd>`</kbd>: toggle file tree view
 </pre>

docs/keybindings/Keybindings_zh.md

@@ -123,6 +123,7 @@ _This file is auto-generated. To update, make the changes in the pkg/i18n direct
   <kbd>o</kbd>: 打开文件
   <kbd>e</kbd>: 编辑文件
   <kbd>space</kbd>: 补丁中包含的切换文件
+  <kbd>a</kbd>: toggle all files included in patch
   <kbd>enter</kbd>: 输入文件以将所选行添加到补丁中（或切换目录折叠）
   <kbd>`</kbd>: 切换文件树视图
 </pre>