[`pyupgrade`] Stabilize `non-pep646-unpack` (`UP044`) (#16632)

Summary
--

Stabilizes UP044, renames the module to match the rule name, and removes
the `PreviewMode` from the test settings.

Test Plan
--

2 closed issues in November, just after the rule was added, otherwise no
issues

crates/ruff_linter/src/codes.rs

@@ -538,7 +538,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Pyupgrade, "041") => (RuleGroup::Stable, rules::pyupgrade::rules::TimeoutErrorAlias),
         (Pyupgrade, "042") => (RuleGroup::Preview, rules::pyupgrade::rules::ReplaceStrEnum),
         (Pyupgrade, "043") => (RuleGroup::Stable, rules::pyupgrade::rules::UnnecessaryDefaultTypeArgs),
-        (Pyupgrade, "044") => (RuleGroup::Preview, rules::pyupgrade::rules::NonPEP646Unpack),
+        (Pyupgrade, "044") => (RuleGroup::Stable, rules::pyupgrade::rules::NonPEP646Unpack),
         (Pyupgrade, "045") => (RuleGroup::Preview, rules::pyupgrade::rules::NonPEP604AnnotationOptional),
         (Pyupgrade, "046") => (RuleGroup::Preview, rules::pyupgrade::rules::NonPEP695GenericClass),
         (Pyupgrade, "047") => (RuleGroup::Preview, rules::pyupgrade::rules::NonPEP695GenericFunction),

crates/ruff_linter/src/rules/pyupgrade/mod.rs

@@ -285,7 +285,6 @@ mod tests {
         let diagnostics = test_path(
             Path::new("pyupgrade/UP044.py"),
             &settings::LinterSettings {
-                preview: PreviewMode::Enabled,
                 unresolved_target_version: PythonVersion::PY311,
                 ..settings::LinterSettings::for_rule(Rule::NonPEP646Unpack)
             },

crates/ruff_linter/src/rules/pyupgrade/rules/mod.rs

@@ -11,6 +11,7 @@ pub(crate) use format_literals::*;
 pub(crate) use lru_cache_with_maxsize_none::*;
 pub(crate) use lru_cache_without_parameters::*;
 pub(crate) use native_literals::*;
+pub(crate) use non_pep646_unpack::*;
 pub(crate) use open_alias::*;
 pub(crate) use os_error_alias::*;
 pub(crate) use outdated_version_block::*;
@@ -36,7 +37,6 @@ pub(crate) use unpacked_list_comprehension::*;
 pub(crate) use use_pep585_annotation::*;
 pub(crate) use use_pep604_annotation::*;
 pub(crate) use use_pep604_isinstance::*;
-pub(crate) use use_pep646_unpack::*;
 pub(crate) use useless_metaclass_type::*;
 pub(crate) use useless_object_inheritance::*;
 pub(crate) use yield_in_for_loop::*;
@@ -54,6 +54,7 @@ mod format_literals;
 mod lru_cache_with_maxsize_none;
 mod lru_cache_without_parameters;
 mod native_literals;
+mod non_pep646_unpack;
 mod open_alias;
 mod os_error_alias;
 mod outdated_version_block;
@@ -79,7 +80,6 @@ mod unpacked_list_comprehension;
 mod use_pep585_annotation;
 mod use_pep604_annotation;
 mod use_pep604_isinstance;
-mod use_pep646_unpack;
 mod useless_metaclass_type;
 mod useless_object_inheritance;
 mod yield_in_for_loop;