[Perl] Small whitespace related improvements (sublimehq#1644)

* [Perl] Allow any kind of whitespace around accessors

The accessor `::` may be surrounded by spaces and tabs. Not sure whether
someone makes use of tabs in such situations, but it should not fail if
one decides to do so.

HEREDOC indention still accepts normal spaces only at the moment as the
amount of spaces in front of the starting and terminating keyword must be
the same which might be tricky to handle if mixed indention is used.

* [Perl] Remove an isolated regexp flag

Inspired by PR sublimehq#1640 this commit removes the isolated (?x) from
the `pragma` context.

Even though no related issues were found this style of flag is used
in the `functions` context already. So this change ensures the same
coding style to be used in both contexts.

Perl/Perl.sublime-syntax

@@ -12,7 +12,7 @@ first_line_match: ^#!.*\bperl\b
 scope: source.perl
 
 variables:
-  break: (?!\w| *::)
+  break: (?!\w|\s*::)
   identifier: '\b[_[:alpha:]]\w*{{break}}'
   module: '\b[_[:upper:]]\w*\b'
   member: '\b[_[:lower:]]\w*\b'
@@ -243,8 +243,8 @@ contexts:
     # SEE: http://perldoc.perl.org/index-pragmas.html
     #      http://perldoc.perl.org/perlmodlib.html#Pragmatic-Modules
     - match: |-
-        \b(?x)
-        (?:attributes|autodie(?:::(?:exception(?:::system)|hints|skip))?|autouse
+        \b(?x:
+           attributes|autodie(?:\s*::\s*(?:exception(?:\s*::\s*system)|hints|skip))?|autouse
           |base|bigint|bignum|bigrat|blib|bytes
           |charnames|constant
           |diagnostics
@@ -260,7 +260,7 @@ contexts:
           |threads|threads::shared
           |utf8
           |vars|vmsish
-          |warnings|warnings::register){{break}}
+          |warnings|warnings\s*::\s*register){{break}}
       scope: storage.modifier.perl
 
 ### [ EXPRESSIONS ]###########################################################
@@ -589,16 +589,16 @@ contexts:
 ### [ CLASSES ]################################################################
 
   class:
-    - match: '{{module}}(?= *(?:::|[#;]|$))'
+    - match: '{{module}}(?=\s*(?:::|[#;]|$))'
       scope: support.class.perl
       push: members-pop
 
   members-pop:
-    - match: ' *(::) *({{module}})'
+    - match: \s*(::)\s*({{module}})
       captures:
         1: punctuation.accessor.double-colon.perl
         2: support.class.perl
-    - match: ' *(::) *({{identifier}})'
+    - match: \s*(::)\s*({{identifier}})
       captures:
         1: punctuation.accessor.double-colon.perl
         2: variable.other.member.perl
@@ -1029,7 +1029,7 @@ contexts:
         1: punctuation.definition.variable.perl
     # $Module::SubModule::member
     # $::SubModule::member
-    - match: ([\$\@\%]#?)({{module}})?(?= *::)
+    - match: ([\$\@\%]#?)({{module}})?(?=\s*::)
       captures:
         1: punctuation.definition.variable.perl
         2: support.class.perl

Perl/syntax_test_perl.pl

@@ -1076,6 +1076,17 @@ =head1 B<--param>
 #      ^^^^^^^^^^^^^^^^^^ meta.import.require.perl
 #                        ^^^^ - meta.import.require.perl
 #      ^^^^^^^ keyword.control.import.require.perl
+eval { require Mail :: Send; };
+#<- support.function.perl
+#^^^ support.function.perl
+#    ^ punctuation.section.block.begin.perl
+#      ^^^^^^^^^^^^^^^^^^^^ meta.import.require.perl
+#              ^^^^ support.class.perl
+#                  ^^^^ - support.class
+#                   ^^ punctuation.accessor.double-colon.perl
+#                      ^^^^ support.class.perl
+#                          ^^^^ - meta.import.require.perl
+#      ^^^^^^^ keyword.control.import.require.perl
 use strict;
 # <- meta.use.perl keyword.control.import.use.perl
 #^^^^^^^^^ meta.use.perl
@@ -1103,7 +1114,6 @@ =head1 B<--param>
 #^^ keyword.control.import.use.perl
 #   ^^^^ support.class.perl
 #       ^ punctuation.terminator.statement.perl
-
 use File::data;
 # <- meta.use.perl keyword.control.import.use.perl
 #^^^^^^^^^^^^^ meta.use.perl
@@ -1112,6 +1122,15 @@ =head1 B<--param>
 #       ^^ punctuation.accessor.double-colon.perl
 #         ^^^^ variable.other.member.perl
 #             ^ punctuation.terminator.statement.perl
+use warnings :: register File :: data;
+# <- meta.use.perl keyword.control.import.use.perl
+#^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ meta.use.perl
+#^^ keyword.control.import.use.perl
+#   ^^^^^^^^^^^^^^^^^^^^ storage.modifier.perl
+#                        ^^^^ support.class.perl
+#                             ^^ punctuation.accessor.double-colon.perl
+#                                ^^^^ variable.other.member.perl
+#                                    ^ punctuation.terminator.statement.perl
 no strict;
 # <- meta.no.perl keyword.declaration.no.perl
 #^^^^^^^^ meta.no.perl