add /_data/*.tsv support (#5985)

* Update data.feature

- add .tsv
- add .csv with `\t`
- add .csv with `;`

* Fix Appveyor with dst-aware cucumber steps

* Check for given content in posts

* mention Ruby > 2.1.0 in docs

* Update history to reflect merge of #5983 [ci skip]

* Update history to reflect merge of #5961 [ci skip]

* Update data_reader.rb

- add .tsv support with tab separated columns
- not adding support for auto-detecting `:col_sep`

ftp://ftp.iana.org/assignments/media-types/text/tab-separated-values
https://www.ietf.org/rfc/rfc4180.txt (CSV)
https://ruby-doc.org/stdlib-2.4.1/libdoc/csv/rdoc/CSV.html

* Update data.feature

don't do semicolons and tabs in .csv within this patch

* Update data.feature

I don't know which component replaced my tab characters by space before.

* Update data.feature

t

* Update data_reader.rb

add a single space to satisfy format checker

features/data.feature

@@ -59,6 +59,20 @@ Feature: Data
     And I should see "Jack" in "_site/index.html"
     And I should see "Leon" in "_site/index.html"
 
+  Scenario: autoload *.tsv files in _data directory
+    Given I have a _data directory
+    And I have a "_data/members.tsv" file with content:
+      """
+      name	age
+      Jack	28
+      Leon	34
+      """
+    And I have an "index.html" page that contains "{% for member in site.data.members %}{{member.name}}{% endfor %}"
+    When I run jekyll build
+    Then the "_site/index.html" file should exist
+    And I should see "Jack" in "_site/index.html"
+    And I should see "Leon" in "_site/index.html"
+
   Scenario: autoload *.yml files in _data directory with space in file name
     Given I have a _data directory
     And I have a "_data/team members.yml" file with content:

lib/jekyll/readers/data_reader.rb

@@ -19,7 +19,7 @@ module Jekyll
       @content
     end
 
-    # Read and parse all .yaml, .yml, .json, and .csv
+    # Read and parse all .yaml, .yml, .json, .csv and .tsv
     # files under <dir> and add them to the <data> variable.
     #
     # dir - The string absolute path of the directory to read.
@@ -30,7 +30,7 @@ module Jekyll
       return unless File.directory?(dir) && !@entry_filter.symlink?(dir)
 
       entries = Dir.chdir(dir) do
-        Dir["*.{yaml,yml,json,csv}"] + Dir["*"].select { |fn| File.directory?(fn) }
+        Dir["*.{yaml,yml,json,csv,tsv}"] + Dir["*"].select { |fn| File.directory?(fn) }
       end
 
       entries.each do |entry|
@@ -56,6 +56,12 @@ module Jekyll
           :headers  => true,
           :encoding => site.config["encoding"],
         }).map(&:to_hash)
+      when ".tsv"
+        CSV.read(path, {
+          :col_sep  => "\t",
+          :headers  => true,
+          :encoding => site.config["encoding"],
+        }).map(&:to_hash)
       else
         SafeYAML.load_file(path)
       end