Let RequirementSource::Path.editable be bool, not Option<bool> (#3693)

Small refactoring of the internal representation. This does not change
`tool.uv.sources`.

crates/distribution-types/src/requirement.rs

@@ -174,7 +174,7 @@ pub enum RequirementSource {
     Path {
         path: PathBuf,
         /// For a source tree (a directory), whether to install as an editable.
-        editable: Option<bool>,
+        editable: bool,
         /// The PEP 508 style URL in the format
         /// `file:///<path>#subdirectory=<subdirectory>`.
         url: VerbatimUrl,
@@ -189,7 +189,7 @@ impl RequirementSource {
             ParsedUrl::Path(local_file) => RequirementSource::Path {
                 path: local_file.path,
                 url,
-                editable: None,
+                editable: false,
             },
             ParsedUrl::Git(git) => RequirementSource::Git {
                 url,

crates/distribution-types/src/resolution.rs

@@ -94,7 +94,7 @@ impl From<&ResolvedDist> for Requirement {
                 Dist::Built(BuiltDist::Path(wheel)) => RequirementSource::Path {
                     path: wheel.path.clone(),
                     url: wheel.url.clone(),
-                    editable: None,
+                    editable: false,
                 },
                 Dist::Source(SourceDist::Registry(sdist)) => RequirementSource::Registry {
                     specifier: pep440_rs::VersionSpecifiers::from(
@@ -121,12 +121,12 @@ impl From<&ResolvedDist> for Requirement {
                 Dist::Source(SourceDist::Path(sdist)) => RequirementSource::Path {
                     path: sdist.path.clone(),
                     url: sdist.url.clone(),
-                    editable: None,
+                    editable: false,
                 },
                 Dist::Source(SourceDist::Directory(sdist)) => RequirementSource::Path {
                     path: sdist.path.clone(),
                     url: sdist.url.clone(),
-                    editable: Some(sdist.editable),
+                    editable: sdist.editable,
                 },
             },
             ResolvedDist::Installed(dist) => RequirementSource::Registry {