Improve documentation and handling of options with spaces

[matthijskooijman]

I've been trying to use git log's -S option and get the output displayed in git. My first try was tig -S foo, which just says tig: No revisions match the given arguments.. Originally I thought that tig just didn't support this flag somehow, then I thought there was a bug in forwarding flags to git log and finally, after some strace experiments and re-reading the documentation more carefully, I realized that I should be using tig -Sfoo without a space and it works as expected.

I realize that this is a necessary limitation of tig not knowing how git log's arguments work and it is actually documented in the manpage:

The first command line parameter not starting with "-" is interpreted as being either a revision specification or a path and will end the option parsing.

However, it is not so obvious and easy to miss, so I'd suggest two improvements:

1. Make it more explicit that spaces should be omitted in the manpage (suggestion below).
2. Let the error message include the revision arguments tried. E.g. if tig -S foo would say: tig: No revisions match the arguments "foo", then I probably would have realized what was going on earlier.

For 1, how about adding a note under OPTIONS:

Note that this means that any arguments to options should be specified together. For example, run tig -Sfoo instead of tig -S foo, and tig --grep=foo instead of tig --grep foo, otherwise foo will be interpreted as a revision rather than an argument to -S.

[blueyed]

Note that while tig -Sfoo works, tig log -Sfoo does not.
(and to use arguments with spaces tig -S"foo bar" can be used)