Invalidate BOM inside plain strings

syntaxes/yaml-1.2.tmLanguage.json

@@ -377,6 +377,10 @@
 					"match": "[\t ]++$",
 					"name": "punctuation.whitespace.separator.yaml"
 				},
+				{
+					"match": "\\x{FEFF}",
+					"name": "invalid.illegal.bom.yaml"
+				},
 				{ "include": "#non-printable" }
 			]
 		},
@@ -511,6 +515,10 @@
 							"match": "[\t ]++$",
 							"name": "punctuation.whitespace.separator.yaml"
 						},
+						{
+							"match": "\\x{FEFF}",
+							"name": "invalid.illegal.bom.yaml"
+						},
 						{ "include": "#non-printable" }
 					]
 				},
@@ -712,6 +720,10 @@
 					"match": ":(?=[\r\n\t ,\\[\\]{}])",
 					"name": "invalid.illegal.multiline-key.yaml"
 				},
+				{
+					"match": "\\x{FEFF}",
+					"name": "invalid.illegal.bom.yaml"
+				},
 				{ "include": "#non-printable" }
 			]
 		},
@@ -730,6 +742,10 @@
 					"match": "[\t ]++$",
 					"name": "punctuation.whitespace.separator.yaml"
 				},
+				{
+					"match": "\\x{FEFF}",
+					"name": "invalid.illegal.bom.yaml"
+				},
 				{ "include": "#non-printable" }
 			]
 		},
@@ -740,6 +756,10 @@
 			"name": "meta.flow.map.key.yaml string.unquoted.other.in.yaml entity.name.tag.yaml",
 			"patterns": [
 				{ "include": "#tag-implicit-plain-in" },
+				{
+					"match": "\\x{FEFF}",
+					"name": "invalid.illegal.bom.yaml"
+				},
 				{ "include": "#non-printable" }
 			]
 		},
@@ -1086,7 +1106,7 @@
 		},
 		"comment": {
 			"comment": "Comments must be separated from other tokens by white space characters. `space`, `tab`, `newline` or `carriage-return`. `#(.*)` causes performance issues",
-			"begin": "(?<= |\t|^)#",
+			"begin": "(?<=[\\x{FEFF}\t ]^)#",
 			"end": "\r|\n",
 			"captures": { "0": { "name": "punctuation.definition.comment.yaml" } },
 			"name": "comment.line.number-sign.yaml",