Update documentation to clean up unnecessary usage of expr. about matchit.cpp

[hugoetchegoyen]

Bowen, now that expr() has been removed, test/optexpr.cpp is meaningless and should be removed too.
Best regfards,
Hugo

[BowenFu]

Hi @hugoetchegoyen, "expr()" will be kept at least until next major release. So it is better to keep the tests.

Since documentation has been updated in #98, I'm going to close this issue.

[hugoetchegoyen]

Ok, but in that case I guess optexpr.cpp should not be cleaned up of unnecessary expr()s. As it is now, both test cases (no_expr and unnecessary_expr) are identical and expr() is not used at all.

[BowenFu]

Ok, but in that case I guess optexpr.cpp should not be cleaned up of unnecessary expr()s. As it is now, both test cases (no_expr and unnecessary_expr) are identical and expr() is not used at all.

That should be a mistake. Will recover that file.

[BowenFu]

Will be fixed by #99