disable Nunjucks when the renderer spcify that

[be5invis]

This PR adds Nunjucks disabling if the renderer claim that it can handle “tags” on its own.
Currently it is not active (i.e., Nunjucks would work) for all existing renderers.

[coveralls]

Coverage increased (+0.004%) to 97.142% when pulling 68568e9 on be5invis:be5invis-disable-nunjucks into b76a7b2 on hexojs:master.

[coveralls]

Coverage increased (+0.004%) to 97.142% when pulling 7c23e3a on be5invis:be5invis-disable-nunjucks into b76a7b2 on hexojs:master.

[coveralls]

Coverage increased (+0.004%) to 97.142% when pulling 16aa813 on be5invis:be5invis-disable-nunjucks into b76a7b2 on hexojs:master.

[NoahDragon]

Could you please keep the old promising style?

promise(
  some code
).then(
  antoher code
)

instead of

promise(
  some code
)
.then(
  another code
)

This will make the change comparison more clearly.

[be5invis]

@NoahDragon Hold on.

[coveralls]

Coverage increased (+0.004%) to 97.142% when pulling 7f0742e on be5invis:be5invis-disable-nunjucks into b76a7b2 on hexojs:master.

[be5invis]

@NoahDragon Finish.

[NoahDragon]

Thank for the PR. IMO, give this decision to renderers is better than to the users. #2478

[NoahDragon]

I'm thinking extend this function to post front matters. Instead of site-wide configuration variable, each post can disable Nunjucks when specified. Do you think this will be feasible and compatible with your change?

#2622

[9662]

Sorry, could you please provide an example of how would a renderer use this feature?

[be5invis]

@9662
I have a custom renderer which is completely not MarkDown and Nunjucks notation may conflict with some of its inputs. That's (originally) why I created this PR. To achieve this, simply add a disableNunjucks property to your renderer function.