chore: remove check underscores

plugin/gomark/parser/bold.go

@@ -22,7 +22,7 @@ func (*BoldParser) Match(tokens []*tokenizer.Token) (ast.Node, int) {
 		return nil, 0
 	}
 	prefixTokenType := prefixTokens[0].Type
-	if prefixTokenType != tokenizer.Asterisk && prefixTokenType != tokenizer.Underscore {
+	if prefixTokenType != tokenizer.Asterisk {
 		return nil, 0
 	}
 

plugin/gomark/parser/bold_italic.go

@@ -21,7 +21,7 @@ func (*BoldItalicParser) Match(tokens []*tokenizer.Token) (ast.Node, int) {
 		return nil, 0
 	}
 	prefixTokenType := prefixTokens[0].Type
-	if prefixTokenType != tokenizer.Asterisk && prefixTokenType != tokenizer.Underscore {
+	if prefixTokenType != tokenizer.Asterisk {
 		return nil, 0
 	}
 

plugin/gomark/parser/horizontal_rule.go

@@ -22,7 +22,7 @@ func (*HorizontalRuleParser) Match(tokens []*tokenizer.Token) (ast.Node, int) {
 	if matchedTokens[0].Type != matchedTokens[1].Type || matchedTokens[0].Type != matchedTokens[2].Type || matchedTokens[1].Type != matchedTokens[2].Type {
 		return nil, 0
 	}
-	if matchedTokens[0].Type != tokenizer.Hyphen && matchedTokens[0].Type != tokenizer.Underscore && matchedTokens[0].Type != tokenizer.Asterisk {
+	if matchedTokens[0].Type != tokenizer.Hyphen && matchedTokens[0].Type != tokenizer.Asterisk {
 		return nil, 0
 	}
 	return &ast.HorizontalRule{

plugin/gomark/parser/horizontal_rule_test.go

@@ -41,12 +41,6 @@ func TestHorizontalRuleParser(t *testing.T) {
 			text:           "-*-",
 			horizontalRule: nil,
 		},
-		{
-			text: "___",
-			horizontalRule: &ast.HorizontalRule{
-				Symbol: "_",
-			},
-		},
 	}
 
 	for _, test := range tests {

plugin/gomark/parser/italic.go

@@ -20,7 +20,7 @@ func (*ItalicParser) Match(tokens []*tokenizer.Token) (ast.Node, int) {
 	}
 
 	prefixTokens := matchedTokens[:1]
-	if prefixTokens[0].Type != tokenizer.Asterisk && prefixTokens[0].Type != tokenizer.Underscore {
+	if prefixTokens[0].Type != tokenizer.Asterisk {
 		return nil, 0
 	}
 	prefixTokenType := prefixTokens[0].Type