Address minor feedback from swiftlang#1604

Author: aciidgh

Sources/Basic/Process.swift

@@ -192,7 +192,7 @@ public final class Process: ObjectIdentifierProtocol {
         self.verbose = verbose
     }
 
-    /// Returns true if the given program is present and executable in search path.
+    /// Returns the path of the the given program if found in the search paths.
     ///
     /// The program can be executable name, relative path or absolute path.
     public static func findExecutable(_ program: String) -> AbsolutePath? {

Sources/Commands/SwiftPackageTool.swift

@@ -328,7 +328,7 @@ public class SwiftPackageTool: SwiftTool<PackageToolOptions> {
                 usage: "Use the legacy scheme generator"),
             generateXcodeParser.add(
                 option: "--watch", kind: Bool.self,
-                usage: "Watch the filesystem and autogenerate the Xcode project if needed"),
+                usage: "Watch for changes to the Package manifest to regenerate the Xcode project"),
             to: {
                 $0.xcodeprojOptions.useLegacySchemeGenerator = $1 ?? false
                 $0.xcodeprojOptions.enableAutogeneration = $2 ?? false

Tests/CommandsTests/PackageToolTests.swift

@@ -504,7 +504,7 @@ final class PackageToolTests: XCTestCase {
                 packageRoot: packageRoot)
 
             let script = try helper.createXcodegenScript(
-                XcodeprojOptions())
+                XcodeprojOptions(xcconfigOverrides: .init("/tmp/overrides.xcconfig")))
 
             XCTAssertEqual(try fs.readFileContents(script), """
                 #!/usr/bin/env bash
@@ -515,7 +515,7 @@ final class PackageToolTests: XCTestCase {
 
                 set -eu
 
-                swift package generate-xcodeproj
+                swift package generate-xcodeproj --xcconfig-overrides /tmp/overrides.xcconfig
 
                 """)
         }