Fix input descriptions

.github/workflows/create-pr-to-update-manifest.yml

@@ -7,7 +7,7 @@ on:
   workflow_call:
     inputs:
       tool-name:
-        description: 'Name of a tool for which PR is created'
+        description: 'Name of the tool for which PR is created'
         required: true
         type: string
 

.github/workflows/get-new-tool-versions.yml

@@ -11,7 +11,7 @@ on:
   workflow_call:
     inputs:
       tool-name:
-        description: 'Name of a tool for which versions are searched'
+        description: 'Name of the tool for which versions are searched'
         required: true
         type: string
       image-url:

.github/workflows/validate-manifest.yml

@@ -8,7 +8,7 @@ on:
   workflow_call:
     inputs:
       tool-name:
-        description: 'Name of a tool for which manifest is validated'
+        description: 'Name of the tool for which manifest is validated'
         required: true
         type: string
       image-url: