Generate var getter for reuseIdentifier, fixes concurrentcy-safe error.

With `let reuseIdentifier = reuseIdentifier()`, Swift 6 would generate this error:

    Let 'R' is not concurrency-safe because non-'Sendable' type '_R' may have shared mutable state

By changing to `var reuseIdentifier: reuseIdentifier { .init() }`, the error goes away.

To be extra safe, made two additional changes (that aren't strictly needed to fix the error):
 - changed all other top-level lets to vars,
 - changed the lets in the reuseIdentifier struct to vars

Sources/RswiftGenerators/ReuseIdentifier+Generator.swift

@@ -26,7 +26,7 @@ extension Reusable {
         groupedReusables.reportWarningsForDuplicatesAndEmpties(source: "reuseIdentifier", result: "reuse identifier", warning: warning)
 
         let letbindings = groupedReusables.uniques
-            .map { $0.generateLetBinding() }
+            .map { $0.generateVarGetter() }
             .sorted { $0.name < $1.name }
 
         let comments = ["This `\(qualifiedName.value)` struct is generated, and contains static references to \(letbindings.count) reuse identifiers."]
@@ -82,8 +82,8 @@ extension Reusable {
         )
     }
 
-    func generateLetBinding() -> LetBinding {
-        LetBinding(
+    func generateVarGetter() -> VarGetter {
+        VarGetter(
             comments: ["Reuse identifier `\(identifier)`."],
             name: SwiftIdentifier(name: identifier),
             typeReference: genericTypeReference,

Sources/RswiftGenerators/StringsTable+Generator.swift

@@ -10,11 +10,11 @@ import RswiftResources
 
 
 extension Struct {
-    public func generateBundleVarGetterForString(name: String) -> VarGetter {
+    public func generateBundleVarGetterForString() -> VarGetter {
         VarGetter(
             deploymentTarget: deploymentTarget,
-            name: SwiftIdentifier(name: name),
-            typeReference: TypeReference(module: .host, rawName: self.name.value),
+            name: name,
+            typeReference: TypeReference(module: .host, rawName: name.value),
             valueCodeString: ".init(bundle: bundle, preferredLanguages: nil, locale: nil)"
         )
     }

Sources/RswiftGenerators/SwiftSyntax/Struct.swift

@@ -549,6 +549,15 @@ extension Struct {
         )
     }
 
+    public func generateVarGetter() -> VarGetter {
+        VarGetter(
+            deploymentTarget: deploymentTarget,
+            name: name,
+            typeReference: TypeReference(module: .host, rawName: self.name.value),
+            valueCodeString: ".init()"
+        )
+    }
+
     public func generateBundleVarGetter(name: String) -> VarGetter {
         VarGetter(
             deploymentTarget: deploymentTarget,

Sources/rswift/RswiftCore.swift

@@ -209,7 +209,7 @@ public struct RswiftCore {
             }
 
             if generators.contains(.string), !stringStruct.isEmpty {
-                stringStruct.generateBundleVarGetterForString(name: "string")
+                stringStruct.generateBundleVarGetterForString()
                 stringStruct.generateBundleFunctionForString(name: "string")
                 stringStruct.generateLocaleFunctionForString(name: "string")
                 stringStruct.generatePreferredLanguagesFunctionForString(name: "string")
@@ -241,7 +241,7 @@ public struct RswiftCore {
             }
 
             if generators.contains(.entitlements), !entitlementsStruct.isEmpty {
-                entitlementsStruct.generateLetBinding()
+                entitlementsStruct.generateVarGetter()
                 entitlementsStruct
             }
 
@@ -258,12 +258,12 @@ public struct RswiftCore {
             }
 
             if generators.contains(.segue), !segueStruct.isEmpty {
-                segueStruct.generateLetBinding()
+                segueStruct.generateVarGetter()
                 segueStruct
             }
 
             if generators.contains(.id), !idStruct.isEmpty {
-                idStruct.generateLetBinding()
+                idStruct.generateVarGetter()
                 idStruct
             }
 
@@ -274,7 +274,7 @@ public struct RswiftCore {
             }
 
             if generators.contains(.reuseIdentifier), !reuseIdentifierStruct.isEmpty {
-                reuseIdentifierStruct.generateLetBinding()
+                reuseIdentifierStruct.generateVarGetter()
                 reuseIdentifierStruct
             }