Update see-also reference to new method name

Author: DougGregor

Sources/SwiftSyntaxMacrosTestSupport/Assertions.swift

@@ -46,8 +46,9 @@ public typealias DiagnosticSpec = SwiftSyntaxMacrosGenericTestSupport.Diagnostic
 /// - testModuleName: The name of the test module to use.
 /// - testFileName: The name of the test file name to use.
 /// - indentationWidth: The indentation width used in the expansion.
-///
-/// - SeeAlso: ``assertMacroExpansion(_:expandedSource:diagnostics:macroSpecs:applyFixIts:fixedSource:testModuleName:testFileName:indentationWidth:file:line:)``
+/// - buildConfiguration: a build configuration that will be made available
+/// to the macro implementation
+/// - SeeAlso: ``assertMacroExpansion(_:expandedSource:diagnostics:macroSpecs:applyFixIts:fixedSource:testModuleName:testFileName:indentationWidth:buildConfiguration:file:line:)``
 /// to also specify the list of conformances passed to the macro expansion.
 public func assertMacroExpansion(
  _ originalSource: String,