ensure markdown export is using only LF as end of line

Web browsers send multiline textarea value with CRLF as end of line.

As the markdown export uses the raw value from database, we need to
replace the CRLF by LF end of lines. Otherwise the file will have both
type of end of lines.

See suivi request: https://linuxfr.org/suivi/export-markdown

Author: Trim

app/views/diaries/show.md.erb

@@ -1,3 +1,3 @@
 <%= render "nodes/front_matter", :content => @diary %>
 
-<%= raw @diary.wiki_body %>
+<%= raw @diary.wiki_body.encode(universal_newline: true) %>

app/views/news/show.md.erb

@@ -1,6 +1,6 @@
 <%= render "nodes/front_matter", :content => @news %>
 
-<%= raw @news.wiki_body %>
+<%= raw @news.wiki_body.encode(universal_newline: true) %>
 
 ----
 
@@ -10,4 +10,4 @@
 
 ----
 
-<%= raw @news.wiki_second_part %>
+<%= raw @news.wiki_second_part.encode(universal_newline: true) %>

app/views/polls/show.md.erb

@@ -1,6 +1,6 @@
 <%= render "nodes/front_matter", :content => @poll %>
 
-<%= raw @poll.wiki_explanations %>
+<%= raw @poll.wiki_explanations.encode(universal_newline: true) %>
 
 <%- @poll.answers.each do |answer| -%>
 * <%= raw answer.answer %>

app/views/posts/show.md.erb

@@ -1,3 +1,3 @@
 <%= render "nodes/front_matter", :content => @post %>
 
-<%= raw @post.wiki_body %>
+<%= raw @post.wiki_body.encode(universal_newline: true) %>

app/views/trackers/show.md.erb

@@ -1,3 +1,3 @@
 <%= render "nodes/front_matter", :content => @tracker %>
 
-<%= raw @tracker.wiki_body %>
+<%= raw @tracker.wiki_body.encode(universal_newline: true) %>

app/views/wiki_pages/show.md.erb

@@ -1,3 +1,3 @@
 <%= render "nodes/front_matter", :content => @wiki_page %>
 
-<%= raw @wiki_page.versions.first.body %>
+<%= raw @wiki_page.versions.first.body.encode(universal_newline: true) %>