enh(brainfuck): Add remaining four commands

Author: davidhcefx

brainfuck.nanorc

@@ -1,7 +1,14 @@
-syntax "brainfuck" "\.bf$"
+syntax "brainfuck" "\.(bf|b)$"
 magic "brainfuck"
+comment ""
 
+# control flow
 color orange "\["
 color orange "]"
+color red "<"
+color red ">"
+# data manipulation
 color cyan "\+"
 color cyan "-"
+color brightgreen ","
+color brightgreen "\."