Update old wiki links (#247)

Part of flutter/flutter#145009

Author: Piinks

analysis_options.yaml

@@ -135,7 +135,7 @@ linter:
     - prefer_contains
     # - prefer_double_quotes # opposite of prefer_single_quotes
     - prefer_equal_for_default_values
-    # - prefer_expression_function_bodies # conflicts with https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#consider-using--for-short-functions-and-methods
+    # - prefer_expression_function_bodies # conflicts with https://github.com/flutter/flutter/blob/master/docs/contributing/Style-guide-for-Flutter-repo.md#consider-using--for-short-functions-and-methods
     - prefer_final_fields
     - prefer_final_in_for_each
     - prefer_final_locals
@@ -148,7 +148,7 @@ linter:
     - prefer_if_null_operators
     - prefer_initializing_formals
     - prefer_inlined_adds
-    # - prefer_int_literals # conflicts with https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#use-double-literals-for-double-constants
+    # - prefer_int_literals # conflicts with https://github.com/flutter/flutter/blob/master/docs/contributing/Style-guide-for-Flutter-repo.md#use-double-literals-for-double-constants
     - prefer_interpolation_to_compose_strings
     - prefer_is_empty
     - prefer_is_not_empty