feat(rule): required alternatives - handle plural form of use case

Author: naiyerasif

Prim/RequiredAlternatives.yml

@@ -25,4 +25,4 @@ swap:
   url:  URL
   URL for: URL of
   an URL: a URL
-  usecase: use case
+  usecases?: use case|use cases

test/fixtures/RequiredAlternatives/test.md

@@ -65,3 +65,4 @@ Hover on an URL to preview the page.
 
 <!-- usecase -->
 Can you provide a specific usecase where this technology would be beneficial?
+We analyzed the usecases to identify potential improvements.

test/snapshots/RequiredAlternatives.log

@@ -25,4 +25,5 @@ test.md:59:76:Prim.RequiredAlternatives:Use 'test case' or 'test cases' instead
 test.md:62:17:Prim.RequiredAlternatives:Use 'URL' instead of 'url'.
 test.md:63:5:Prim.RequiredAlternatives:Use 'URL of' instead of 'URL for'.
 test.md:64:10:Prim.RequiredAlternatives:Use 'a URL' instead of 'an URL'.
-test.md:67:28:Prim.RequiredAlternatives:Use 'use case' instead of 'usecase'.
+test.md:67:28:Prim.RequiredAlternatives:Use 'use case' or 'use cases' instead of 'usecase'.
+test.md:68:17:Prim.RequiredAlternatives:Use 'use case' or 'use cases' instead of 'usecases'.