Enphasize keyboard shortcuts with a dedicated style

Also add release notes related to the #387 merge.

-- Fluctuat nec mergitur

client/components/cards/attachments.jade

@@ -7,7 +7,7 @@ template(name="cardAttachmentsPopup")
       a.js-upload-clipboard-image {{_ 'clipboard'}}
 
 template(name="previewClipboardImagePopup")
-  p {{_ "paste-or-dragdrop"}}
+  p <kbd>Ctrl</kbd>+<kbd>V</kbd> {{_ "paste-or-dragdrop"}}
   img.preview-clipboard-image()
   button.primary.js-upload-pasted-image {{_ 'upload'}}
 

client/components/main/keyboardShortcuts.styl

@@ -14,11 +14,6 @@
         padding: 5px 8px
         margin: 5px
         font-size: 18px
-        font-weight: bold
-        background: white
-        border-radius: 3px
-        border: 1px solid darken(white, 10%)
-        box-shadow: 0px 2px 3px rgba(0, 0, 0, 0.15)
 
     .shortcuts-list-item-action
       font-size: 1.4em

client/components/main/layouts.styl

@@ -172,6 +172,15 @@ dl, dt
 dd
   margin: 0 0 16px 24px
 
+kbd
+  padding: 1px 3px
+  margin: 3px
+  font-weight: bold
+  background: darken(white, 2%)
+  border-radius: 3px
+  border: 1px solid darken(white, 10%)
+  box-shadow: 0px 2px 3px rgba(0, 0, 0, 0.15)
+
 .clear
   clear: both