refactor: Centralize some more styling (#16124)

### What does this PR try to resolve?

On its own, this does nothing. These styles aren't used anywhere else
and so this doesn't increase re-use.

My primary goal with this is having a central place to document this for
other applications to track that want to mirror our style. In
particular, I'm hoping to take advantage of the `UPDATE` colors in
rustup.

This also makes it easier for us to audit all of the values for
consistency.

### How to test and review this PR?

Author: weihanglo

src/cargo/ops/cargo_update.rs

@@ -1058,11 +1058,11 @@ impl PackageChangeKind {
 
     pub fn style(&self) -> anstyle::Style {
         match self {
-            Self::Added => style::NOTE,
-            Self::Removed => style::ERROR,
-            Self::Upgraded => style::GOOD,
-            Self::Downgraded => style::WARN,
-            Self::Unchanged => anstyle::Style::new().bold(),
+            Self::Added => style::UPDATE_ADDED,
+            Self::Removed => style::UPDATE_REMOVED,
+            Self::Upgraded => style::UPDATE_UPGRADED,
+            Self::Downgraded => style::UPDATE_DOWNGRADED,
+            Self::Unchanged => style::UPDATE_UNCHANGED,
         }
     }
 }

src/cargo/ops/tree/mod.rs

@@ -8,6 +8,7 @@ use crate::core::{Package, PackageId, PackageIdSpec, PackageIdSpecQuery, Workspa
 use crate::ops::resolve::SpecsAndResolvedFeatures;
 use crate::ops::{self, Packages};
 use crate::util::CargoResult;
+use crate::util::style;
 use crate::{drop_print, drop_println};
 use anyhow::Context as _;
 use graph::Graph;
@@ -477,13 +478,9 @@ fn print_dependencies<'a>(
 
 fn edge_line_color(kind: EdgeKind) -> anstyle::Style {
     match kind {
-        EdgeKind::Dep(DepKind::Normal) => anstyle::Style::new() | anstyle::Effects::DIMMED,
-        EdgeKind::Dep(DepKind::Build) => {
-            anstyle::AnsiColor::Blue.on_default() | anstyle::Effects::BOLD
-        }
-        EdgeKind::Dep(DepKind::Development) => {
-            anstyle::AnsiColor::Cyan.on_default() | anstyle::Effects::BOLD
-        }
-        EdgeKind::Feature => anstyle::AnsiColor::Magenta.on_default() | anstyle::Effects::DIMMED,
+        EdgeKind::Dep(DepKind::Normal) => style::DEP_NORMAL,
+        EdgeKind::Dep(DepKind::Build) => style::DEP_BUILD,
+        EdgeKind::Dep(DepKind::Development) => style::DEP_DEV,
+        EdgeKind::Feature => style::DEP_FEATURE,
     }
 }

src/cargo/util/style.rs

@@ -12,3 +12,20 @@ pub const GOOD: Style = AnsiColor::BrightGreen.on_default().effects(Effects::BOL
 pub const VALID: Style = AnsiColor::BrightCyan.on_default().effects(Effects::BOLD);
 pub const INVALID: Style = annotate_snippets::renderer::DEFAULT_WARNING_STYLE;
 pub const TRANSIENT: Style = annotate_snippets::renderer::DEFAULT_HELP_STYLE;
+
+pub const UPDATE_ADDED: Style = NOTE;
+pub const UPDATE_REMOVED: Style = ERROR;
+pub const UPDATE_UPGRADED: Style = GOOD;
+pub const UPDATE_DOWNGRADED: Style = WARN;
+pub const UPDATE_UNCHANGED: Style = anstyle::Style::new().bold();
+
+pub const DEP_NORMAL: Style = anstyle::Style::new().effects(anstyle::Effects::DIMMED);
+pub const DEP_BUILD: Style = anstyle::AnsiColor::Blue
+    .on_default()
+    .effects(anstyle::Effects::BOLD);
+pub const DEP_DEV: Style = anstyle::AnsiColor::Cyan
+    .on_default()
+    .effects(anstyle::Effects::BOLD);
+pub const DEP_FEATURE: Style = anstyle::AnsiColor::Magenta
+    .on_default()
+    .effects(anstyle::Effects::DIMMED);