fix(website): links corrected (apache#28333)

Author: frankzimper

CONTRIBUTING.md

@@ -20,5 +20,5 @@ Contributions are welcome and are greatly appreciated! Every
 little bit helps, and credit will always be given.
 
 All matters related to contributions have moved to [this section of
-the official Superset documentation](https://superset.apache.org/docs/contributing/contributing/). Source for the documentation is
+the official Superset documentation](https://superset.apache.org/docs/contributing/). Source for the documentation is
 [located here](https://github.com/apache/superset/tree/master/docs/docs).

docs/docs/contributing/contributing.mdx

@@ -88,7 +88,7 @@ text strings from Superset's UI. You can jump into the existing
 language dictionaries at
 `superset/translations/<language_code>/LC_MESSAGES/messages.po`, or
 even create a dictionary for a new language altogether.
-See [Translating](#translating) for more details.
+See [Translating](howtos#contribute-translations) for more details.
 
 ### Ask Questions