Remove 'However' from methoddoc.

The negation/contrast word 'however' may be confusing/misleading since the sentence supports the argument to not introduce required-ness by imports/tests which occurs when this practice is not followed.

PiperOrigin-RevId: 217701269
diff --git a/absl/flags/_validators.py b/absl/flags/_validators.py
index 02b508e..d34baf2 100644
--- a/absl/flags/_validators.py
+++ b/absl/flags/_validators.py
@@ -340,9 +340,8 @@
       app.run()
 
   Because validation happens at app.run() we want to ensure required-ness
-  is enforced at that time.  However, you generally do not want to force
-  users who import your code to have additional required flags for their
-  own binaries or tests.
+  is enforced at that time. You generally do not want to force users who import
+  your code to have additional required flags for their own binaries or tests.
 
   Args:
     flag_name: str, name of the flag