remove #[inline] on lambdas

[kivikakk]

Fixes #218.

Per rust-lang/rust#49291 (comment), #[inline] has no effect on lambdas, and rustc has stopped allowing this in nightly.

[kivikakk]

I'd like to test that this actually fixes the problem locally, but it's unclear to me quite how to do that. (do I set up an alternate registry?? that sounds like Not Fun.)

[Kroisse]

I think it can be proven by compiling it.

https://github.com/pest-parser/pest/blob/master/grammars/src/lib.rs#L20-L32

[kivikakk]

I'm not sure how that helps: on rust nightly, it attempts to build meta, which uses pest_derive 1.0.6, which doesn't have this change, so the resulting generated code fails.

[Kroisse]

I've tried that by adding [patch.crates-io] section to use the local version of pest_derive, but it's failed because pest_derive is depends on pest_meta so they make a circular dependency.

I think that is the only solution releasing 1.0.7 with this patch. It's possible because it still can be compiled on rustc 1.25 stable.

[dragostis]

Looks good.

[Kroisse]

@kivikakk I've tried to fix on v1.0.6 instead master and it works.