Add a "Mark commit as base commit for rebase" command

This allows to do the equivalent of "git rebase --onto <target> <base>", by
first marking the <base> commit with the new command, and then selecting the
target branch and invoking the usual rebase command there.

docs/keybindings/Keybindings_en.md

@@ -84,6 +84,7 @@ _Legend: `<c-b>` means ctrl+b, `<a-b>` means alt+b, `B` means shift+b_
   <kbd>&lt;c-j&gt;</kbd>: Move commit down one
   <kbd>&lt;c-k&gt;</kbd>: Move commit up one
   <kbd>v</kbd>: Paste commits (cherry-pick)
+  <kbd>B</kbd>: Mark commit as base commit for rebase
   <kbd>A</kbd>: Amend commit with staged changes
   <kbd>a</kbd>: Set/Reset commit author
   <kbd>t</kbd>: Revert commit

docs/keybindings/Keybindings_ja.md

@@ -103,6 +103,7 @@ _Legend: `<c-b>` means ctrl+b, `<a-b>` means alt+b, `B` means shift+b_
   <kbd>&lt;c-j&gt;</kbd>: コミットを1つ下に移動
   <kbd>&lt;c-k&gt;</kbd>: コミットを1つ上に移動
   <kbd>v</kbd>: コミットを貼り付け (cherry-pick)
+  <kbd>B</kbd>: Mark commit as base commit for rebase
   <kbd>A</kbd>: ステージされた変更でamendコミット
   <kbd>a</kbd>: Set/Reset commit author
   <kbd>t</kbd>: コミットをrevert

docs/keybindings/Keybindings_ko.md

@@ -265,6 +265,7 @@ _Legend: `<c-b>` means ctrl+b, `<a-b>` means alt+b, `B` means shift+b_
   <kbd>&lt;c-j&gt;</kbd>: 커밋을 1개 아래로 이동
   <kbd>&lt;c-k&gt;</kbd>: 커밋을 1개 위로 이동
   <kbd>v</kbd>: 커밋을 붙여넣기 (cherry-pick)
+  <kbd>B</kbd>: Mark commit as base commit for rebase
   <kbd>A</kbd>: Amend commit with staged changes
   <kbd>a</kbd>: Set/Reset commit author
   <kbd>t</kbd>: 커밋 되돌리기

docs/keybindings/Keybindings_nl.md

@@ -143,6 +143,7 @@ _Legend: `<c-b>` means ctrl+b, `<a-b>` means alt+b, `B` means shift+b_
   <kbd>&lt;c-j&gt;</kbd>: Verplaats commit 1 naar beneden
   <kbd>&lt;c-k&gt;</kbd>: Verplaats commit 1 naar boven
   <kbd>v</kbd>: Plak commits (cherry-pick)
+  <kbd>B</kbd>: Mark commit as base commit for rebase
   <kbd>A</kbd>: Wijzig commit met staged veranderingen
   <kbd>a</kbd>: Set/Reset commit author
   <kbd>t</kbd>: Commit ongedaan maken

docs/keybindings/Keybindings_pl.md

@@ -69,6 +69,7 @@ _Legend: `<c-b>` means ctrl+b, `<a-b>` means alt+b, `B` means shift+b_
   <kbd>&lt;c-j&gt;</kbd>: Przenieś commit 1 w dół
   <kbd>&lt;c-k&gt;</kbd>: Przenieś commit 1 w górę
   <kbd>v</kbd>: Wklej commity (przebieranie)
+  <kbd>B</kbd>: Mark commit as base commit for rebase
   <kbd>A</kbd>: Popraw commit zmianami z poczekalni
   <kbd>a</kbd>: Set/Reset commit author
   <kbd>t</kbd>: Odwróć commit

docs/keybindings/Keybindings_ru.md

@@ -151,6 +151,7 @@ _Связки клавиш_
   <kbd>&lt;c-j&gt;</kbd>: Переместить коммит вниз на один
   <kbd>&lt;c-k&gt;</kbd>: Переместить коммит вверх на один
   <kbd>v</kbd>: Вставить отобранные коммиты (cherry-pick)
+  <kbd>B</kbd>: Mark commit as base commit for rebase
   <kbd>A</kbd>: Править последний коммит с проиндексированными изменениями
   <kbd>a</kbd>: Установить/убрать автора коммита
   <kbd>t</kbd>: Отменить коммит

docs/keybindings/Keybindings_zh-CN.md

@@ -147,6 +147,7 @@ _Legend: `<c-b>` means ctrl+b, `<a-b>` means alt+b, `B` means shift+b_
   <kbd>&lt;c-j&gt;</kbd>: 下移提交
   <kbd>&lt;c-k&gt;</kbd>: 上移提交
   <kbd>v</kbd>: 粘贴提交（拣选）
+  <kbd>B</kbd>: Mark commit as base commit for rebase
   <kbd>A</kbd>: 用已暂存的更改来修补提交
   <kbd>a</kbd>: Set/Reset commit author
   <kbd>t</kbd>: 还原提交

docs/keybindings/Keybindings_zh-TW.md

@@ -191,6 +191,7 @@ _說明：`<c-b>` 表示 Ctrl+B、`<a-b>` 表示 Alt+B，`B`表示 Shift+B_
   <kbd>&lt;c-j&gt;</kbd>: 向下移動提交
   <kbd>&lt;c-k&gt;</kbd>: 向上移動提交
   <kbd>v</kbd>: 貼上提交 (揀選)
+  <kbd>B</kbd>: Mark commit as base commit for rebase
   <kbd>A</kbd>: 使用已預存的更改修正提交
   <kbd>a</kbd>: 設置/重設提交作者
   <kbd>t</kbd>: 還原提交