Only write to file the formatted code when it is different to the current one

[gonzalobf]

Fixes #231. I couldn't find any test that checks the writing to but let me know if you think it is needed and I'll try to implement one.

I used stats to check if it works:

$ stat rebar.config | grep -F 'Modify'                                                                                                                                            0s
Modify: 2021-01-06 09:38:08.204419183 +0000
$ _build/release/bin/erlfmt -w "{src,include,test}/*.{hrl,erl}" rebar.config
$ stat rebar.config | grep -F 'Modify'                                                                                                                                            0s
Modify: 2021-01-06 09:38:08.204419183 +0000

[kvelicka]

@michalmuskala any thoughts on this?

[michalmuskala]

Hi @kvelicka. Thank you so much for your contribution. I'm sorry about the delay.

We've been quite busy the last couple days. I'll get back to you as soon as I can.

[kvelicka]

Thanks for the quick reply! No worries and no rush, was just making sure that this was on someone's radar.

Credit for the code is all to @gonzalobf too!

[awalterschulze]

We have decided to merge this as is and created an issue to tackle an optimization #238

[awalterschulze]

Thank you for bringing this to our attention and fixing it <3