[bug] `r <Tab>` does nothing

[AlexGuo1998]

If you want to change a character to <Tab> in vim, you could type r <Tab>. However in vim-mode-plus, this does nothing but hides the cursor (until re-open buffer).

This is useful when formatting code. For example: changing space in #define abc 123 to tab, to make it tidy.

debug info

```json { "atom": "1.33.0", "platform": "win32", "release": "10.0.17763", "vmpVersion": "1.36.0", "vmpConfig": { "smoothScrollOnRedrawCursorLine": true, "smoothScrollOnRedrawCursorLineDuration": 100, "updateRegisterOnChangeOrSubstitute": true, "useClipboardAsDefaultRegister": false, "useSmartcaseForSearch": true } } ``` `atom --version`: ``` Atom : 1.33.0 Electron: 2.0.11 Chrome : 61.0.3163.100 Node : 8.9.3 ``` vim-mode-plus version: 1.36.0 OS version: Windows 10 Professional 64bit, 1809 (17763.134)

Checklist

You have to check all before open issue.

• [x] Provide your environment info clipped by Vim Mode Plus: Clip Debug Info command.
• [x] Try with latest Atom and latest vim-mode-plus.
• [x] Pick a descriptive and non-ambiguous subject
• [x] Express "what" you want(feature? config option?, behavior change?) in short sentence(not long!).
• [x] Contrast current behavior if you want to change current behavior, with sample text, operation(keystroke) and result.
• [x] Include real use case so that maintainer can understand "why" you need help.
• [x] Include Atom(atom --version), vim-mode-plus version, and OS version(e.g. macOS Sierra 10.12.3).
• [x] If keybinding issue, Read this.