fix ada filename mixedcase with - object oriented

Derived types use caracter '.' in package name. But in the filename dot
are replaced by '-' .

For exemple :
```ada
package Mother_Package.Daughter_Package is
    -- ...
end Mother_Package.Daughter_Package;
```
is in a file named : Mother_Package-Daughter_Package.ads

So function ada_case(word) change the '-' in filename to dot in the
package name with mixedcase.

UltiSnips/ada.snippets

@@ -5,7 +5,9 @@ global !p
 def ada_case(word):
 	out = word[0].upper()
 	for i in range(1, len(word)):
-		if word[i - 1] == '_':
+		if word[i] == '-':
+			out = out + '.'
+		elif word[i - 1] == '_' or word[i - 1] == '-':
 			out = out + word[i].upper()
 		else:
 			out = out + word[i]