Improve grammar scripts (#3350)

* Remove trailing spaces

* Setup Bundler in some scripts

* Update grammar index

* Make prune-grammars script to be callable in a script directory

* Prune unused xquery grammar repo

source.xq by language-jsoniq is actual tm_scope for XQuery.

* Remove xquery submodule

git submodule deinit vendor/grammars/xquery/
git rm vendor/grammars/xquery/

* Fix invocation of script/list-grammars

This fixes #3339.

* Make add-grammars script to be callable in a script directory

* Generate samples.json before running list-grammars

list-grammars requires linguist.

script/list-grammars

@@ -1,19 +1,20 @@
 #!/usr/bin/env ruby
 
+require "bundler/setup"
 require "linguist"
 require "json"
 require "yaml"
 
 class GrammarList
-  
+
   ROOT = File.expand_path "../../", __FILE__
-  
+
   def initialize
     @submodules     = load_submodules()
     @sources        = load_sources()
     @language_names = load_languages()
   end
-  
+
   # Load .gitmodules
   def load_submodules
     submodules = {}
@@ -29,14 +30,14 @@ class GrammarList
     end
     submodules
   end
-  
+
   # Grab the name of each language, sorted case-insensitively
   def load_languages
     Linguist::Language.all.map(&:name).sort do |a, b|
       a.downcase() <=> b.downcase()
     end
   end
-  
+
   # Load grammars.yml
   def load_sources
     sources = {}
@@ -46,7 +47,7 @@ class GrammarList
     end
     sources
   end
-  
+
   # Shorten a repository URL
   def shorten(url)
     if url =~ /^https?:\/\/(?:www\.)?github\.com\/([^\/]+\/[^\/]+)/i
@@ -57,7 +58,7 @@ class GrammarList
       url.replace(/^https?:\/\/(?:www\.)?/i, "")
     end
   end
-  
+
   # Markdown: Generate grammar list
   def to_markdown
     markdown = ""
@@ -87,7 +88,7 @@ class GrammarList
 
     markdown
   end
-  
+
   # Update the file displaying the reader-friendly list of grammar repos
   def update_readme
     readme = "#{ROOT}/vendor/README.md"