open in_explorer: wording on Mac OS @ cmd palette

it's a bit hackier than the side bar because .sublime-commands doesn't
support the 'platform' key. We still expose only one command however,
just expose open_in_explorer under two caption with an argument to
hide/show on different platforms.

This pattern could be extended to AppCommand if needed elsewhere. Right
now it isn't.

fix #18

Author: math2001

FileManager.sublime-commands

@@ -17,7 +17,17 @@
     },
     {
         "caption": "File Manager: Open In Explorer",
-        "command": "fm_open_in_explorer"
+        "command": "fm_open_in_explorer",
+        "args": {
+            "visible_on_platforms": ["windows", "linux"]
+        }
+    },
+    {
+        "caption": "File Manager: Open In Finder",
+        "command": "fm_open_in_explorer",
+        "args": {
+            "visible_on_platforms": ["osx"]
+        }
     },
     {
         "caption": "File Manager: Open In Browser",

commands/open_in_explorer.py

@@ -4,7 +4,8 @@
 
 
 class FmOpenInExplorerCommand(AppCommand):
-    def run(self, paths=None, *args, **kwargs):
+    def run(self, visible_on_platforms, paths=None):
+        # visible_on_platforms is just used by is_visible
         self.window = get_window()
         self.view = get_view()
 
@@ -20,5 +21,5 @@ def run(self, paths=None, *args, **kwargs):
                     {"dir": os.path.dirname(path), "file": os.path.basename(path)},
                 )
 
-    def is_visisble(self, **args):
-        return True
+    def is_visible(self, visible_on_platforms, paths=None):
+        return sublime.platform() in visible_on_platforms and super().is_visible()