Fix the regular expression for whitespace in love/search-forums

We need to replace whitespace with plus signs for the URL we create.
The code attempts to match whitespace using ‘\\s+’ but this is not
correct.  Emacs uses ‘\\s-’ to represent whitespace, so the function
needs to use ‘\\s-+’ instead.
Rewrite love/automatically-enable to use save-excursion

This is a better approach since the function uses goto-char to jump to
the beginning of the buffer to search for LÖVE functions.  There is a
chance a user may open a Lua file through a bookmarked point, for
example, so in that case we would not want the existing behavior of
moving the point to the start of the buffer.  By using save-excursion
we can avoid this potential problem.
Rename love/automatically-enable to love/possibly-enable-mode

This name is more accurate since the function will not always enable
the minor mode.