cmd/clef: add spaces in README.md table (ethereum#29077)

Add space after links in so they are clickable in vscode.

cmd/clef/README.md

@@ -916,7 +916,7 @@ There are a couple of implementation for a UI. We'll try to keep this list up to
 
 | Name | Repo | UI type| No external resources| Blocky support| Verifies permissions | Hash information | No secondary storage | Statically linked| Can modify parameters|
 | ---- | ---- | -------| ---- | ---- | ---- |---- | ---- | ---- | ---- |
-| QtSigner| https://github.com/holiman/qtsigner/| Python3/QT-based| :+1:| :+1:| :+1:| :+1:| :+1:| :x: |  :+1: (partially)|
-| GtkSigner| https://github.com/holiman/gtksigner| Python3/GTK-based| :+1:| :x:| :x:| :+1:| :+1:| :x: |  :x: |
-| Frame | https://github.com/floating/frame/commits/go-signer| Electron-based| :x:| :x:| :x:| :x:| ?| :x: |  :x: |
-| Clef UI| https://github.com/ethereum/clef-ui| Golang/QT-based| :+1:| :+1:| :x:| :+1:| :+1:| :x: |  :+1: (approve tx only)|
+| QtSigner| https://github.com/holiman/qtsigner/ | Python3/QT-based| :+1:| :+1:| :+1:| :+1:| :+1:| :x: |  :+1: (partially)|
+| GtkSigner| https://github.com/holiman/gtksigner | Python3/GTK-based| :+1:| :x:| :x:| :+1:| :+1:| :x: |  :x: |
+| Frame | https://github.com/floating/frame/commits/go-signer | Electron-based| :x:| :x:| :x:| :x:| ?| :x: |  :x: |
+| Clef UI| https://github.com/ethereum/clef-ui | Golang/QT-based| :+1:| :+1:| :x:| :+1:| :+1:| :x: |  :+1: (approve tx only)|