refactor: Centralize CONTEXT style

This is similar to #16124 in making it easier for others to see what
styles cargo uses and copy them.

Author: epage

src/cargo/ops/registry/info/view.rs

@@ -2,7 +2,7 @@ use std::collections::HashMap;
 use std::io::Write;
 
 use crate::core::Shell;
-use crate::util::style::{ERROR, HEADER, LITERAL, NOP, WARN};
+use crate::util::style::{CONTEXT, ERROR, HEADER, LITERAL, NOP, WARN};
 use crate::{
     CargoResult, GlobalContext,
     core::{
@@ -26,7 +26,7 @@ pub(super) fn pretty_view(
     let header = HEADER;
     let error = ERROR;
     let warn = WARN;
-    let context = annotate_snippets::renderer::DEFAULT_CONTEXT_STYLE;
+    let context = CONTEXT;
 
     let mut shell = gctx.shell();
     let verbosity = shell.verbosity();

src/cargo/util/style.rs

@@ -12,6 +12,7 @@ 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 CONTEXT: Style = annotate_snippets::renderer::DEFAULT_CONTEXT_STYLE;
 
 pub const UPDATE_ADDED: Style = NOTE;
 pub const UPDATE_REMOVED: Style = ERROR;