refactor: make clear SourceId serialization will change in v4

src/cargo/core/source_id.rs

@@ -692,7 +692,7 @@ impl fmt::Display for SourceId {
                 // Don't replace the URL display for git references,
                 // because those are kind of expected to be URLs.
                 write!(f, "{}", self.inner.url)?;
-                // TODO(-Znext-lockfile-bump): set it to true when stabilizing
+                // TODO(-Znext-lockfile-bump): set it to true when the default is
                 // lockfile v4, because we want Source ID serialization to be
                 // consistent with lockfile.
                 if let Some(pretty) = reference.pretty_ref(false) {

src/cargo/sources/git/source.rs

@@ -162,7 +162,7 @@ impl<'cfg> Debug for GitSource<'cfg> {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
         write!(f, "git repo at {}", self.remote.url())?;
 
-        // TODO(-Znext-lockfile-bump): set it to true when stabilizing
+        // TODO(-Znext-lockfile-bump): set it to true when the default is
         // lockfile v4, because we want Source ID serialization to be
         // consistent with lockfile.
         match self.manifest_reference.pretty_ref(false) {

src/cargo/util/toml_mut/dependency.rs

@@ -893,7 +893,7 @@ impl std::fmt::Display for GitSource {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         let git_ref = self.git_ref();
 
-        // TODO(-Znext-lockfile-bump): set it to true when stabilizing
+        // TODO(-Znext-lockfile-bump): set it to true when the default is
         // lockfile v4, because we want Source ID serialization to be
         // consistent with lockfile.
         if let Some(pretty_ref) = git_ref.pretty_ref(false) {