chore: fix sorbet config comment, trailing newline, and blank lines in hidden.rbi

Author: nijeesh-stream

sorbet/config

@@ -1,4 +1,8 @@
 --dir
 .
 --ignore=vendor/bundle,spec,sorbet/rbi/sorbet-typed
---disable-watchman
+# sorbet/rbi/sorbet-typed contains community stubs generated for Sorbet 0.5.
+# Sorbet 0.6 defaults unsigned RBI files to typed: strict, causing 7017 errors
+# in these stale stubs. They cover dev tools (rake, rspec, rubocop) that don't
+# need type checking. Migrate to Tapioca in a follow-up to replace all stubs.
+--disable-watchman

sorbet/rbi/hidden-definitions/hidden.rbi

@@ -4607,7 +4607,6 @@ class Gem::SpecFetcher
 
   def specs(); end
 
-
   def tuples_for(source, type, gracefully_ignore=T.unsafe(nil)); end
 end
 
@@ -4727,7 +4726,6 @@ class IO
 
   def wait(*arg); end
 
-
   def wait_writable(*arg); end
 end