Fix show TN book intro bug

* Set SHOW_TN_BOOK_INTRO in .env to true
* Fix bug in parsing module where parsing of tn content was not
sharing the settings.SHOW_TN_BOOK_INTRO variable for use in
conditional inclusion of TN book intros, but instead was using its own
local boolean for the same purpose - thus changes to config in
settings was not having an effect.

.env

@@ -43,7 +43,7 @@ USE_GIT_CLI=true
 
 # Content team doesn't want TN book intros to show in DOC.
 # future, if desired we could have them show by sleec
-SHOW_TN_BOOK_INTRO=false
+SHOW_TN_BOOK_INTRO=true
 
 # If true, then check USFM content for certain USFM structural defects
 # and attempt a fix so that the USFM can then be parsed.

backend/document/domain/parsing.py

@@ -779,7 +779,7 @@ def tn_book_content(
     resource_dir: str,
     resource_requests: Sequence[ResourceRequest],
     layout_for_print: bool,
-    include_tn_book_intros: bool = False,
+    show_tn_book_intro: bool = settings.SHOW_TN_BOOK_INTRO,
 ) -> TNBook:
     chapter_verses = tn_chapter_verses(
         resource_dir,
@@ -788,7 +788,7 @@ def tn_book_content(
         resource_requests,
     )
     book_intro = ""
-    if include_tn_book_intros:
+    if show_tn_book_intro:
         book_intro = book_intro_markdown(resource_dir, resource_lookup_dto.book_code)
         if book_intro:
             book_intro = markdown_transformer.remove_sections(book_intro)