Fixing link with the docs of regexp syntax.

ee/app/views/shared/push_rules/_form.html.haml

@@ -29,7 +29,7 @@
   = f.text_field :commit_message_regex, class: "form-control", placeholder: 'Example: Fixes \d+\..*'
   .form-text.text-muted
     All commit messages must match this
-    = link_to 'Ruby regular expression', 'http://www.ruby-doc.org/core-2.1.1/Regexp.html'
+    = link_to 'regular expression', 'https://github.com/google/re2/wiki/Syntax'
     to be pushed.
     If this field is empty it allows any commit message.
     For example you can require that an issue number is always mentioned in the commit message.
@@ -39,7 +39,7 @@
   = f.text_field :commit_message_negative_regex, class: "form-control", placeholder: 'Example: ssh\:\/\/'
   .form-text.text-muted
     No commit message is allowed to match this
-    = link_to 'Ruby regular expression', 'http://www.ruby-doc.org/core-2.1.1/Regexp.html'
+    = link_to 'regular expression', 'https://github.com/google/re2/wiki/Syntax'
     to be pushed.
     If this field is empty it allows any commit message.
     For example you can require that no commit message contains any links.
@@ -49,7 +49,7 @@
   = f.text_field :branch_name_regex, class: "form-control", placeholder: 'Example: (feature|hotfix)\/*'
   .form-text.text-muted
     All branch names must match this
-    = link_to 'Ruby regular expression', 'http://www.ruby-doc.org/core-2.1.1/Regexp.html'
+    = link_to 'regular expression', 'https://github.com/google/re2/wiki/Syntax'
     to be pushed.
     If this field is empty it allows any branch name.
 
@@ -58,7 +58,7 @@
   = f.text_field :author_email_regex, class: "form-control", placeholder: 'Example: @my-company.com$'
   .form-text.text-muted
     All commit author's email must match this
-    = link_to 'Ruby regular expression', 'http://www.ruby-doc.org/core-2.1.1/Regexp.html'
+    = link_to 'regular expression', 'https://github.com/google/re2/wiki/Syntax'
     to be pushed.
     If this field is empty it allows any email.
 
@@ -67,7 +67,7 @@
   = f.text_field :file_name_regex, class: "form-control", placeholder: 'Example: (jar|exe)$'
   .form-text.text-muted
     All commited filenames must not match this
-    = link_to 'Ruby regular expression', 'http://www.ruby-doc.org/core-2.1.1/Regexp.html'
+    = link_to 'regular expression', 'https://github.com/google/re2/wiki/Syntax'
     to be pushed.
     If this field is empty it allows any filenames.