* add hotkey `Ctrl+Down/⌘+Down` to fetch directly
* keep translation keys of en_US in order
* add translations for zh_CN and zh_TW
* do NOT using namespace under `SourceGit`
* use `⇧` instead of `Shift` in hotkey tips
* hotkey mismatch on macOS
* hotkeys to start fetch/pull/push directly not work on macOS
* remove the hotkey of `Create Branch` context menu item
- there are other objects (such as branch and tag) also have the `Create Branch` context menu item without hotkeys
- on macOS, we already use `⌘+B` to create branch with selected commit, not `Ctrl + B`
Signed-off-by: leo <longshuang@msn.cn>
