avoid collision of key binding on win32 and linux

[colin-kiegel]

atom-core defines this keybindings for 'f3' but none for 'f1'

'.platform-win32 atom-text-editor, .platform-linux atom-text-editor':
'f3': 'find-and-replace:find-next'

This pull requests makes the racer-keybinding work on win32 and linux by default.

[alkama]

Those collisions are unavoidable and noone can tell that F1 wont collide with something else that ppl use.
Wouldn't it be better to document in the Readme how each user can bind the feature to his favorite key?

[colin-kiegel]

@alkama: Yes and No.

• Yes: General collisions of key-bindings of other packages are unavoidable. And noone can tell that F1 wont collide with something else that ppl use.
• and No: This is a collision with atom-core (not on osx, but on linux and on windows). Those can and should be avoided imo.

[alkama]

Makes sense

[colin-kiegel]

Of course one should check if the alternative F1 collides with OS key bindings (like help) on windows and osx. It works fine on ubuntu gnome.