Update how_to_add_new_language.md

Added a follow up PR that implements dictionary lookup for Serbian.

Author: nciric

documents/how_to_add_new_language.md

@@ -7,8 +7,8 @@ Adding a new language requires multiple steps:
 
 The following steps with help you identify files that need to be added or changed, and will guide you in rule writing and lexicon preparation.
 
-NOTE: Take a look at [PR #40](https://github.com/unicode-org/inflection/pull/40) for example on how to add initial language support.
-In general, to bootstrap your progress look for grammatically similar language that's already supported, e.g. if you are adding Serbian look for existing Russian or Croatian implementation.
+NOTE: Take a look at [PR #40](https://github.com/unicode-org/inflection/pull/40) and [PR #111](https://github.com/unicode-org/inflection/pull/111) for example on how to add initial language support based on dictionary lookup only.
+In general, to bootstrap your progress look for grammatically similar language that's already supported, e.g. if you are adding Serbian look for existing Russian implementation.
 This will help you find most of the files you need to add/change and will speed up implementation of the rules and lexicons.
 
 ## Mark your language as supported