typo in -Xswiftc w--warnings-as-errors

Co-authored-by: Mahdi Bahrami <github@mahdibm.com>

Author: sebsto

.github/workflows/pull_request.yml

@@ -20,7 +20,7 @@ jobs:
             linux_5_9_arguments_override: "-Xswiftc --warnings-as-errors --explicit-target-dependency-import-check error"
             linux_5_10_arguments_override: "-Xswiftc --warnings-as-errors --explicit-target-dependency-import-check error"
             linux_nightly_6_0_arguments_override: "-Xswiftc --warnings-as-errors --explicit-target-dependency-import-check error"
-            linux_nightly_main_arguments_override: "-Xswiftc w--warnings-as-errors --explicit-target-dependency-import-check error"
+            linux_nightly_main_arguments_override: "-Xswiftc --warnings-as-errors --explicit-target-dependency-import-check error"
 
     swift-6-language-mode:
         name: Swift 6 Language Mode