add redirect bc utf pg doesnt exist below v4.3 (#677)

* add redirect bc utf pg doesnt exist below v4.3

* fix to 4.2

* add trailing slashes

Author: rustagir

config/redirects

@@ -17,4 +17,5 @@ raw: ${prefix}/stable -> ${base}/current/
 [*-v5.0]: ${prefix}/${version}/quick-start/download-and-install/ -> ${base}/${version}/quick-start/
 [*-v5.0]: ${prefix}/${version}/quick-start/next-steps/ -> ${base}/${version}/quick-start/
 
-[v4.3-master]: ${prefix}/${version}/fundamentals/utf8-validation -> ${base}/${version}/fundamentals/bson/utf8-validation/
+[v4.3-master]: ${prefix}/${version}/fundamentals/utf8-validation/ -> ${base}/${version}/fundamentals/bson/utf8-validation/
+[*-v4.2]: ${prefix}/${version}/fundamentals/utf8-validation/ -> ${base}/${version}/