1. Log in to your dashboard--> Design- -> Edit HTML
2. Click on "Expand Widget Templates"
3. Search "Ctrl+F" and find the following code: 

<a class='comment-link' expr:href='data:post.addCommentUrl' 
expr:onclick='data:post.addCommentOnclick'><b:if cond='data:post.numComments == 1'>1
 <data:top.commentLabel/><b:else/><data:post.numComments/>
 <data:top.commentLabelPlural/></b:if></a>

You will find the code in two places but you need to modify just the first one.

4. Replace the blue and red code with the text you want to appear . The blue code is for a single comment and the red one for multiple ones. ( 1 comment = blue; 2 comments = red)

Exemple:

<a class='comment-link' expr:href='data:post.addCommentUrl' 
expr:onclick='data:post.addCommentOnclick'><b:if cond='data:post.numComments == 1'>1
 Feedback<b:else/><data:post.numComments/>
 Feedbacks</b:if></a>

Save the template and you are done.