syntax: allow spaces after table delimiter. fix #894 (#895)

Author: ebousse

syntaxes/Asciidoctor.json

@@ -1974,7 +1974,7 @@
       "patterns": [
         {
           "name": "markup.table.asciidoc",
-          "begin": "^(\\|===)$",
+          "begin": "^(\\|===)\\s*$",
           "beginCaptures": {
             "0": {
               "name": "markup.table.delimiter.asciidoc"
@@ -1998,7 +1998,7 @@
               "include": "#tables-includes"
             }
           ],
-          "end": "^(\\1)$",
+          "end": "^(\\1)\\s*$",
           "endCaptures": {
             "0": {
               "name": "markup.table.delimiter.asciidoc"