plugin text syntaxes: fixed default syntax

sat/plugins/plugin_misc_text_syntaxes.py

@@ -42,7 +42,7 @@ import re
 
 CATEGORY = D_("Composition")
 NAME = "Syntax"
-_SYNTAX_XHTML = "XHTML"
+_SYNTAX_XHTML = "xhtml"  # must be lower case
 _SYNTAX_CURRENT = "@CURRENT@"
 
 # TODO: check/adapt following list
@@ -157,6 +157,7 @@ class TextSyntaxes(object):
     SYNTAX_MARKDOWN = "markdown"
     SYNTAX_TEXT = "text"
     syntaxes = {}
+    # default_syntax must be lower case
     default_syntax = SYNTAX_XHTML
 
     params = """
@@ -409,7 +410,7 @@ class TextSyntaxes(object):
             "flags": flags,
         }
         if TextSyntaxes.OPT_DEFAULT in flags:
-            TextSyntaxes.default_syntaxe = key
+            TextSyntaxes.default_syntax = key
 
         self._updateParamOptions()