Clarify documentation of password quality check modules

Be clearer in the info documentation that the part of the policy
name before the colon is the name of the module, not the static
string "module".  State explicitly that "builtin" can be used as the
module name to identify built-in policies.

Use the same terminology in kadm5_pwcheck(3) as the info documentation,
changing test-name to policy-name and vendor to module-name.  State
explicitly how the module name and policy name are used to select which
policies to run.

Rephrase a few sentences, add a paragraph break, and fix a few typos
for clarity.

Signed-off-by: Love Hornquist Astrand <lha@h5l.org>

doc/setup.texi

@@ -422,16 +422,18 @@ controls, add lines similar to the following to your
 
 @example
 [password_quality]
-	policies = external-check builtin:minimum-length module:policyname
+	policies = external-check builtin:minimum-length modulename:policyname
 	external_program = /bin/false
 	policy_libraries = @var{library1.so} @var{library2.so}
 @end example
 
 In @samp{[password_quality]policies} the module name is optional if
 the policy name is unique in all modules (members of
-@samp{policy_libraries}).
+@samp{policy_libraries}).  All built-in policies can be qualified with
+a module name of @samp{builtin} to unambiguously specify the built-in
+policy and not a policy by the same name from a loaded module.
 
-The built-in polices are
+The built-in policies are
 
 @itemize @bullet
 

lib/kadm5/kadm5_pwcheck.3

@@ -77,16 +77,17 @@ library.
 .Pp
 There are two versions of the shared object API; the old version (0)
 is deprecated, but still supported.  The new version (1) supports
-multiple password quality checking modules in the same shared object.
+multiple password quality checking policies in the same shared object.
 See below for details.
 .Pp
-The password quality checker will run over all tests that are
+The password quality checker will run all policies that are
-configured by the user.
+configured by the user.  If any policy rejects the password, the password
+will be rejected.
 .Pp
-Module names are of the form
+Policy names are of the form
-.Ql vendor:test-name
+.Ql module-name:policy-name
-or, if the the test name is unique enough, just
+or, if the the policy name is unique enough, just
-.Ql test-name .
+.Ql policy-name .
 .Sh IMPLEMENTING A PASSWORD QUALITY CHECKING SHARED OBJECT
 (This refers to the version 1 API only.)
 .Pp
@@ -101,10 +102,16 @@ Its
 .Ft name
 and
 .Ft vendor
-fields should be contain the obvious information and
+fields should contain the obvious information.
+.Ft name
+must match the
+.Ql module-name
+portion of the policy name (the part before the colon), if the policy name
+contains a colon, or the policy will not be run.
 .Ft version
 should be
 .Dv KADM5_PASSWD_VERSION_V1 .
+.Pp
 .Ft funcs
 contains an array of
 .Ft "struct kadm5_pw_policy_check_func"
@@ -113,8 +120,14 @@ structures that is terminated with an entry whose
 component is
 .Dv NULL .
 The
+.Ft name
+field of the array must match the
+.Ql policy-name
+portion of a policy name (the part after the colon, or the complete policy
+name if there is no colon) specified by the user or the policy will not be
+run.  The
 .Ft func
-Fields of the array elements are functions that are exported by the
+fields of the array elements are functions that are exported by the
 module to be called to check the password.  They get the following
 arguments:  the Kerberos context, principal, password, a tuning parameter, and
 a pointer to a message buffer and its length.  The tuning parameter