[Workspace] Improve error message for minimum required tools version

<rdar://problem/44194498> Diagnostic when building packages which use manifest v3 is confusing

Author: aciidgh

Sources/Workspace/Diagnostics.swift

@@ -256,8 +256,9 @@ public enum WorkspaceDiagnostics {
             name: "org.swift.diags.workspace.incompatible-tools-version",
             description: {
                 $0 <<< "package at" <<< { "'\($0.rootPackagePath.asString)'" }
-                $0 <<< "requires a minimum Swift tools version of" <<< { $0.requiredToolsVersion.description }
-                $0 <<< { "(currently \($0.currentToolsVersion.description))" }
+                $0 <<< "is using Swift tools version" <<< { $0.currentToolsVersion.description }
+                $0 <<< "which is no longer supported; use" <<< { $0.requiredToolsVersion.description }
+                $0 <<< "or newer instead"
             })
 
         /// The path of the package.

Tests/FunctionalTests/ToolsVersionTests.swift

@@ -103,7 +103,7 @@ class ToolsVersionTests: XCTestCase {
                 _ = try SwiftPMProduct.SwiftBuild.execute([], packagePath: primaryPath)
                 XCTFail()
             } catch SwiftPMProductError.executionFailure(_, _, let stderr) {
-                XCTAssert(stderr.contains("equires a minimum Swift tools version of 10000.1.0 (currently \(ToolsVersion.currentToolsVersion)"), stderr)
+                XCTAssert(stderr.contains("is using Swift tools version 4.2.0 which is no longer supported; use 10000.1.0 or newer instead"), stderr)
             }
 
             // Write the manifest with incompatible sources.

Tests/WorkspaceTests/WorkspaceTests.swift

@@ -1264,17 +1264,17 @@ final class WorkspaceTests: XCTestCase {
         }
         workspace.checkPackageGraph(roots: ["Bar"]) { (graph, diagnostics) in
             DiagnosticsEngineTester(diagnostics) { result in
-                result.check(diagnostic: .equal("package at '/tmp/ws/roots/Bar' requires a minimum Swift tools version of 4.1.0 (currently 4.0.0)"), behavior: .error, location: "/tmp/ws/roots/Bar")
+                result.check(diagnostic: .equal("package at '/tmp/ws/roots/Bar' is using Swift tools version 4.0.0 which is no longer supported; use 4.1.0 or newer instead"), behavior: .error, location: "/tmp/ws/roots/Bar")
             }
         }
         workspace.checkPackageGraph(roots: ["Foo", "Bar"]) { (graph, diagnostics) in
             DiagnosticsEngineTester(diagnostics) { result in
-                result.check(diagnostic: .equal("package at '/tmp/ws/roots/Bar' requires a minimum Swift tools version of 4.1.0 (currently 4.0.0)"), behavior: .error, location: "/tmp/ws/roots/Bar")
+                result.check(diagnostic: .equal("package at '/tmp/ws/roots/Bar' is using Swift tools version 4.0.0 which is no longer supported; use 4.1.0 or newer instead"), behavior: .error, location: "/tmp/ws/roots/Bar")
             }
         }
         workspace.checkPackageGraph(roots: ["Baz"]) { (graph, diagnostics) in
             DiagnosticsEngineTester(diagnostics) { result in
-                result.check(diagnostic: .equal("package at '/tmp/ws/roots/Baz' requires a minimum Swift tools version of 4.0.0 (currently 3.1.0)"), behavior: .error, location: "/tmp/ws/roots/Baz")
+                result.check(diagnostic: .equal("package at '/tmp/ws/roots/Baz' is using Swift tools version 3.1.0 which is no longer supported; use 4.0.0 or newer instead"), behavior: .error, location: "/tmp/ws/roots/Baz")
             }
         }
     }