Add language highlight to the wiki page

[electric-coder]

The examples wiki page could use some Python language highlighting.

So instead of:

import hfst
tr1 = hfst.regex('foo:bar')
tr2 = hfst.regex('bar:baz')
tr1.compose(tr2)
print(tr1)

like so:

import hfst
tr1 = hfst.regex('foo:bar')
tr2 = hfst.regex('bar:baz')
tr1.compose(tr2)
print(tr1)