Fix highlighting of decorators preceded by ':'

Author: vpetrovykh

grammars/MagicPython.cson

@@ -56,6 +56,8 @@ repository:
         (?! \\s | \\# | [rR]?(\\'\\'\\'|\\"\\"\\"|\\'|\\") | $)
         |
         (?<=\\'\\'\\'|\\"\\"\\"|\\'|\\")
+        |
+        ^(?= \\s* @)
       
     '''
     endCaptures:

grammars/MagicPython.syntax.yaml

@@ -86,6 +86,8 @@ repository:
         (?! \s | \# | [rR]?(\'\'\'|\"\"\"|\'|\") | $)
         |
         (?<=\'\'\'|\"\"\"|\'|\")
+        |
+        ^(?= \s* @)
     endCaptures:
       '1': {name: punctuation.definition.string.end.python}
     patterns:

grammars/MagicPython.tmLanguage

@@ -81,6 +81,8 @@
   (?! \s | \# | [rR]?(\'\'\'|\"\"\"|\'|\") | $)
   |
   (?<=\'\'\'|\"\"\"|\'|\")
+  |
+  ^(?= \s* @)
 </string>
         <key>endCaptures</key>
         <dict>

test/docstrings/regr1.py

@@ -0,0 +1,21 @@
+#:
+    @asd
+    def foo():
+        pass
+
+
+
+#             : comment.line.number-sign.python, punctuation.definition.comment.python, source.python
+:             : comment.line.number-sign.python, source.python
+              : meta.function.decorator.python, source.python
+@             : entity.name.function.decorator.python, meta.function.decorator.python, source.python
+asd           : entity.name.function.decorator.python, meta.function.decorator.python, source.python
+              : meta.function.python, source.python
+def           : meta.function.python, source.python, storage.type.function.python
+              : meta.function.python, source.python
+foo           : entity.name.function.python, meta.function.python, source.python
+(             : meta.function.parameters.python, meta.function.python, punctuation.definition.parameters.begin.python, source.python
+)             : meta.function.parameters.python, meta.function.python, punctuation.definition.parameters.end.python, source.python
+:             : meta.function.python, punctuation.section.function.begin.python, source.python
+              : source.python
+pass          : keyword.control.flow.python, source.python