yaml: handle plain strings w/ non-initial quotes

yaml.jsf

@@ -23,11 +23,15 @@
 	"#"		line_comment	recolor=-1
 	" "		line_start
 
+:maybe_idlecomment Comment
+	*		idle		noeat
+	"#"		line_comment	recolor=-1
+
 :idle Constant
-	*		idle
+	*		plain_scalar	noeat
 	"\n"		line_start
+	" "		maybe_idlecomment
 	"%"		directive	recolor=-1
-	" "		maybe_line_comment
 	"'"		string_sq_1	recolor=-1
 	"\""		string_dq_1	recolor=-1
 	"{[]}"		brace		recolor=-1
@@ -35,9 +39,15 @@
 	"*&"		maybe_reference
 	"!"		maybe_typecast
 
+:plain_scalar Constant
+	*		plain_scalar
+	"\t"		bad_tab		recolor=-1
+	"\n"		line_start	noeat
+
 :maybe_key Idle
 	*		maybe_key1	recolor=-1 mark
-	"\n%#'\"{[]}*&!"	idle		noeat
+	"\n"		line_start
+	"%#'\"{[]}*&!"	idle		noeat
 	"-"		maybe_block1	mark
 
 :maybe_key1 Constant
@@ -56,10 +66,6 @@
 :bad_tab BadTab
 	*		line_start	noeat
 
-:maybe_line_comment Comment
-	*		idle		noeat
-	"#"		line_comment
-
 :line_comment Comment
 	*		line_comment
 	"\n"		line_start