Add smartIndent to codemirror (#3810)

* add smartIndent config to codemirror

* add indentWithTabs config to codemirror

* make default tabSize same value as indentUnit

* make tab and enter do smart indentation

plugins/tiddlywiki/codemirror/config/extraKeysTW.tid

@@ -11,5 +11,7 @@ type: json
 	"Alt-T": "transposeChars",
 	"Alt-U": "undoSelection",
 	"Shift-Alt-U": "redoSelection",
-	"Cmd-U": ""
+	"Cmd-U": "",
+	"Tab": "indentAuto()",
+	"Enter": "newLineAndIndent()"
 }

plugins/tiddlywiki/codemirror/config/indentWithTabs.tid

@@ -0,0 +1,3 @@
+title: $:/config/codemirror/indentWithTabs
+type: bool
+text: true

plugins/tiddlywiki/codemirror/config/smartIndent.tid

@@ -0,0 +1,3 @@
+title: $:/config/codemirror/smartIndent
+type: bool
+text: true

plugins/tiddlywiki/codemirror/config/tabSize.tid

@@ -1,3 +1,3 @@
 title: $:/config/codemirror/tabSize
 type: integer
-text: 4
+text: 2