Improve error message for overlapping sources (#5934)

Author: valeriyvan

Sources/PackageLoading/PackageBuilder.swift

@@ -102,7 +102,7 @@ extension ModuleError: CustomStringConvertible {
         case .invalidPublicHeadersDirectory(let name):
             return "public headers (\"include\") directory path for '\(name)' is invalid or not contained in the target"
         case .overlappingSources(let target, let sources):
-            return "target '\(target)' has sources overlapping sources: " +
+            return "target '\(target)' has overlapping sources: " +
                 sources.map({ $0.description }).joined(separator: ", ")
         case .multipleTestEntryPointFilesFound(let package, let files):
             return "package '\(package)' has multiple test entry point files: " +

Tests/PackageLoadingTests/PackageBuilderTests.swift

@@ -706,8 +706,8 @@ class PackageBuilderTests: XCTestCase {
                     type: .test),
             ]
         )
-        PackageBuilderTester(manifest, in: fs) { package, diagnotics in
-            diagnotics.check(diagnostic: "target 'barTests' has sources overlapping sources: \(bar.appending(components: "Tests", "barTests.swift"))", severity: .error)
+        PackageBuilderTester(manifest, in: fs) { package, diagnostics in
+            diagnostics.check(diagnostic: "target 'barTests' has overlapping sources: \(bar.appending(components: "Tests", "barTests.swift"))", severity: .error)
         }
 
         manifest = Manifest.createRootManifest(