fixed "\\" from not parsing

moonscript/parse.lua

@@ -212,7 +212,9 @@ local build_grammar = wrap(function()
 	local Name = sym"@" * Name / mark"self" + Name + Space * "..." / trim
 
 	local function simple_string(delim, x)
-		return C(symx(delim)) * C((P('\\'..delim) + (1 - S('\r\n'..delim)))^0) * sym(delim) / mark"string"
+		return C(symx(delim)) * C((P('\\'..delim) +
+			"\\\\" +
+			(1 - S('\r\n'..delim)))^0) * sym(delim) / mark"string"
 	end
 
 	-- wrap if statement if there is a conditional decorator

tests/inputs/string.moon

@@ -27,3 +27,7 @@ hola = [===[
 mm = [[well trhere]]
 
 
+x = "\\"
+x = "a\\b"
+x = "\\\n"
+x = "\""

tests/outputs/string.lua

@@ -12,3 +12,7 @@ local hi_there = [[  hi there
 local well = [==[ "helo" ]==]
 local hola = [===[  eat noots]===]
 local mm = [[well trhere]]
+local x = "\\"
+x = "a\\b"
+x = "\\\n"
+x = "\""