Fix fontification of namespaces in using-statements.

Namespaces can add with numbers (like SomeContract.v3).
Update tests.

Author: josteink

csharp-mode-tests.el

@@ -121,6 +121,7 @@
                         "Reference" 'font-lock-constant-face
                         "Under_scored" 'font-lock-constant-face
                         "WithNumbers09.Ok" 'font-lock-constant-face
+                        "WithNumbers09.OkV2" 'font-lock-constant-face
                         ))
 
 (ert-deftest fontification-of-namespace-statements ()
@@ -129,6 +130,7 @@
                         "Reference" 'font-lock-constant-face
                         "Under_scored" 'font-lock-constant-face
                         "WithNumbers09.Ok" 'font-lock-constant-face
+                        "WithNumbers09.OkV2" 'font-lock-constant-face
                         ))
 
 (defun list-repeat-once (mylist)

csharp-mode.el

@@ -773,7 +773,7 @@ to work properly with code that includes attributes."
                 "[ \t\n\f\v\r]*="
                 "[ \t\n\f\v\r]*"
                 "\\)?"
-                "\\(\\(?:[A-Za-z0-9_]+\\.\\)*[A-Za-z_]+\\)"
+                "\\(\\(?:[A-Za-z0-9_]+\\.\\)*[A-Za-z0-9_]+\\)"
                 "[ \t\n\f\v\r]*;")
               (2 font-lock-constant-face t t)
               (3 font-lock-constant-face))

test-files/namespace-fontification.cs

@@ -5,3 +5,11 @@ namespace Reference {
 namespace Under_Scored {
 
 }
+
+namespace WithNumbers09.Ok {
+
+}
+
+namespace WithNumbers09.OkV2 {
+
+}

test-files/using-fontification.cs

@@ -1,3 +1,4 @@
 using Reference;
 using Under_scored;
 using WithNumbers09.Ok;
+using WithNumbers09.OkV2;