docs: align the input wording

I'd like to keep the descriptions of the inputs aligned where
possible/useful to avoid confusion about what they do.

README.md

@@ -109,7 +109,8 @@ The action can be configured with the following optional [inputs](https://docs.g
 
 Default: `false` (disabled)
 
-Controls wheather the assignees of the original pull request should be added to the backports.
+Controls whether to copy the assignees from the original pull request to the backport pull request.
+By default, the assignees are not copied.
 
 ### `copy_labels_pattern`
 
@@ -123,13 +124,15 @@ By default, no labels are copied.
 
 Default: `false` (disabled)
 
-Controls wheather the "milestone" of the original pull request should be added to the backports.
+Controls whether to copy the milestone from the original pull request to the backport pull request.
+By default, the milestone is not copied.
 
 ### `copy_reviewers`
 
 Default: `false` (disabled)
 
-Controls wheather the reviewers of the original pull request should be added to the backports.
+Controls whether to copy the reviewers from the original pull request to the backport pull request.
+By default, the reviewers are not copied.
 
 ### `github_token`
 

action.yml

@@ -5,7 +5,7 @@ author: korthout
 inputs:
   copy_assignees:
     description: >
-      Whether or not to copy the assignees from the original pull request to the backport pull request.
+      Controls whether to copy the assignees from the original pull request to the backport pull request.
       By default, the assignees are not copied.
     default: false
   copy_labels_pattern:
@@ -15,12 +15,12 @@ inputs:
       By default, no labels are copied.
   copy_milestone:
     description: >
-      Whether or not to copy the milestone from the original pull request to the backport pull request.
+      Controls whether to copy the milestone from the original pull request to the backport pull request.
       By default, the milestone is not copied.
     default: false
   copy_reviewers:
     description: >
-      Whether or not to copy the reviewers from the original pull request to the backport pull request.
+      Controls whether to copy the reviewers from the original pull request to the backport pull request.
       By default, the reviewers are not copied.
     default: false
   github_token: