refactor(help): Remove redundant required check

With us moving the required de-duplication up a level, it made this
check redundant.  By removing this check, we're more likely to have an
item in the `incls` which forces a smart usage and reduces the chance of
an `[ARGS]` or `[OPTIONS]`, so a couple of tests changed.

src/parse/validator.rs

@@ -601,9 +601,7 @@ impl<'help, 'cmd> Validator<'help, 'cmd> {
             .filter(|arg_id| matcher.check_explicit(arg_id, ArgPredicate::IsPresent))
             .filter(|n| {
                 // Filter out the args we don't want to specify.
-                self.cmd
-                    .find(n)
-                    .map_or(true, |a| !a.is_hide_set() && !self.required.contains(&a.id))
+                self.cmd.find(n).map_or(true, |a| !a.is_hide_set())
             })
             .cloned()
             .chain(incl)

tests/builder/double_require.rs

@@ -16,7 +16,7 @@ static ONLY_B_ERROR: &str = "error: The following required arguments were not pr
     -c
 
 USAGE:
-    prog [OPTIONS] -b -c
+    prog -b -c
 
 For more information try --help
 ";
@@ -25,7 +25,7 @@ static ONLY_C_ERROR: &str = "error: The following required arguments were not pr
     -b
 
 USAGE:
-    prog [OPTIONS] -c -b
+    prog -c -b
 
 For more information try --help
 ";

tests/builder/require.rs

@@ -170,7 +170,7 @@ static POSITIONAL_REQ_IF_VAL: &str = "error: The following required arguments we
     <opt>
 
 USAGE:
-    clap-test <flag> <foo> <opt> [ARGS]
+    clap-test <flag> <foo> <opt>
 
 For more information try --help
 ";