Prefer squiggly heredoc in specs for conflicts

This fixes false positives when running `overcommit -r`.

Now, we no longer need to exclude those specs when checking for
conflicts.

scripts/lint-conflicts.sh

 #!/bin/sh
 
-output=`git grep -En '^<<<<<<< ' -- . ':(exclude)spec/lib/gitlab/conflict/file_spec.rb' ':(exclude)spec/lib/gitlab/git/conflict/parser_spec.rb'`
+output=`git grep -En '^<<<<<<< '`
 echo $output
 test -z "$output"

spec/lib/gitlab/conflict/file_spec.rb

@@ -153,47 +153,47 @@ describe Gitlab::Conflict::File do
 
     context 'with an example file' do
       let(:raw_conflict_content) do
-        <<FILE
+        <<~FILE
             # Ensure there is no match line header here
             def username_regexp
               default_regexp
             end
 
-<<<<<<< files/ruby/regex.rb
-def project_name_regexp
+          <<<<<<< files/ruby/regex.rb
+          def project_name_regexp
             /\A[a-zA-Z0-9][a-zA-Z0-9_\-\. ]*\z/
-end
+          end
 
-def name_regexp
+          def name_regexp
             /\A[a-zA-Z0-9_\-\. ]*\z/
-=======
-def project_name_regex
+          =======
+          def project_name_regex
             %r{\A[a-zA-Z0-9][a-zA-Z0-9_\-\. ]*\z}
-end
+          end
 
-def name_regex
+          def name_regex
             %r{\A[a-zA-Z0-9_\-\. ]*\z}
->>>>>>> files/ruby/regex.rb
-end
+          >>>>>>> files/ruby/regex.rb
+          end
 
-# Some extra lines
-# To force a match line
-# To be created
+          # Some extra lines
+          # To force a match line
+          # To be created
 
-def path_regexp
+          def path_regexp
             default_regexp
-end
+          end
 
-<<<<<<< files/ruby/regex.rb
-def archive_formats_regexp
+          <<<<<<< files/ruby/regex.rb
+          def archive_formats_regexp
             /(zip|tar|7z|tar\.gz|tgz|gz|tar\.bz2|tbz|tbz2|tb2|bz2)/
-=======
-def archive_formats_regex
+          =======
+          def archive_formats_regex
             %r{(zip|tar|7z|tar\.gz|tgz|gz|tar\.bz2|tbz|tbz2|tb2|bz2)}
->>>>>>> files/ruby/regex.rb
-end
+          >>>>>>> files/ruby/regex.rb
+          end
 
-def git_reference_regexp
+          def git_reference_regexp
             # Valid git ref regexp, see:
             # https://www.kernel.org/pub/software/scm/git/docs/git-check-ref-format.html
             %r{
@@ -213,19 +213,19 @@ def git_reference_regexp
               (?<!\.lock)               (?# rule #1)
               (?<![\/.])                (?# rule #6-7)
             }x
-end
+          end
 
-protected
+          protected
 
-<<<<<<< files/ruby/regex.rb
-def default_regexp
+          <<<<<<< files/ruby/regex.rb
+          def default_regexp
             /\A[.?]?[a-zA-Z0-9][a-zA-Z0-9_\-\.]*(?<!\.git)\z/
-=======
-def default_regex
+          =======
+          def default_regex
             %r{\A[.?]?[a-zA-Z0-9][a-zA-Z0-9_\-\.]*(?<!\.git)\z}
->>>>>>> files/ruby/regex.rb
-end
-FILE
+          >>>>>>> files/ruby/regex.rb
+          end
+        FILE
       end
 
       let(:sections) { conflict_file.sections }

spec/lib/gitlab/git/conflict/parser_spec.rb

@@ -10,8 +10,8 @@ describe Gitlab::Git::Conflict::Parser do
 
     context 'when the file has valid conflicts' do
       let(:text) do
-        <<CONFLICT
-module Gitlab
+        <<~CONFLICT
+            module Gitlab
               module Regexp
                 extend self
 
@@ -19,34 +19,34 @@ module Gitlab
                   default_regexp
                 end
 
-<<<<<<< files/ruby/regex.rb
+            <<<<<<< files/ruby/regex.rb
                 def project_name_regexp
                   /\A[a-zA-Z0-9][a-zA-Z0-9_\-\. ]*\z/
                 end
 
                 def name_regexp
                   /\A[a-zA-Z0-9_\-\. ]*\z/
-=======
+            =======
                 def project_name_regex
                   %r{\A[a-zA-Z0-9][a-zA-Z0-9_\-\. ]*\z}
                 end
 
                 def name_regex
                   %r{\A[a-zA-Z0-9_\-\. ]*\z}
->>>>>>> files/ruby/regex.rb
+            >>>>>>> files/ruby/regex.rb
                 end
 
                 def path_regexp
                   default_regexp
                 end
 
-<<<<<<< files/ruby/regex.rb
+            <<<<<<< files/ruby/regex.rb
                 def archive_formats_regexp
                   /(zip|tar|7z|tar\.gz|tgz|gz|tar\.bz2|tbz|tbz2|tb2|bz2)/
-=======
+            =======
                 def archive_formats_regex
                   %r{(zip|tar|7z|tar\.gz|tgz|gz|tar\.bz2|tbz|tbz2|tb2|bz2)}
->>>>>>> files/ruby/regex.rb
+            >>>>>>> files/ruby/regex.rb
                 end
 
                 def git_reference_regexp
@@ -73,17 +73,17 @@ module Gitlab
 
                 protected
 
-<<<<<<< files/ruby/regex.rb
+            <<<<<<< files/ruby/regex.rb
                 def default_regexp
                   /\A[.?]?[a-zA-Z0-9][a-zA-Z0-9_\-\.]*(?<!\.git)\z/
-=======
+            =======
                 def default_regex
                   %r{\A[.?]?[a-zA-Z0-9][a-zA-Z0-9_\-\.]*(?<!\.git)\z}
->>>>>>> files/ruby/regex.rb
+            >>>>>>> files/ruby/regex.rb
                 end
               end
-end
-CONFLICT
+            end
+        CONFLICT
       end
 
       let(:lines) do