Justification for this feature is added in the docs.

Precedent for the precise syntax: Hugo.

Hugo puts this syntax behind a preference named headerIds, and automatic
header ID generation behind a preference named autoHeaderIds, with both
enabled by default. I have not implemented a switch to disable this.

My suggestion for a workaround for the improbable case of desiring a
literal “{#…}” at the end of a header is to replace `}` with `}`.

The algorithm I have used is not identical to [that
which Hugo uses][0], because Hugo’s looks to work at the source level,
whereas here we work at the pulldown-cmark event level, which is
generally more sane, but potentially limiting for extremely esoteric
IDs.

Practical differences in implementation from Hugo (based purely on
reading [blackfriday’s implementation][0], not actually trying it):

- I believe Hugo would treat `# Foo {#*bar*}` as a heading with text
  “Foo” and ID `*bar*`, since it is working at the source level; whereas
  this code turns it into a heading with HTML `Foo {#<em>bar</em>}`, as
  it works at the pulldown-cmark event level and doesn’t go out of its
  way to make that work (I’m not familiar with pulldown-cmark, but I get
  the impression that you could make it work Hugo’s way on this point).
  The difference should be negligible: only *very* esoteric hashes would
  include magic Markdown characters.

- Hugo will automatically generate an ID for `{#}`, whereas what I’ve
  coded here will yield a blank ID instead (which feels more correct to
  me—`None` versus `Some("")`, and all that).

In practice the results should be identical.

Fixes #433.

[0]: a477dd1646/block.go (L218-L234)

Added and clarified a few things that would probably have saved me from
raising getzola/zola#691.

To also process the ones found in templates

Closes #669

Closes #674

* bump version in deployment docs

Close #586

Add sublime-syntax for Nix expression language

docs(changelog): fix formatting in v0.7.0 changelog

This is based on [1] and converted to sublime-syntax using [2].

[1] https://github.com/wmertens/sublime-nix
[2] https://github.com/aziz/SublimeSyntaxConvertor

v0.7.0

This reverts commit 1815155c1d.

Closes #667

Add some missing words to the creating a theme page

strip wrapping whitespace from newline outward from shortcodes

Update t-rex.tileserver.ch

Sort sitemap elements by permalink

This feature was originally reported in #257 and got fixed in
3a2dab59743e8d193a80ddb1aa1932e1b5462322, however it seems this
got lost during development.

Closes #661
Ref #257

use svg icon in comparison table, tighten notes prose

specify proper sitemap schema

update zola version on deployment docs

use travis "minimal" vm in the documentation

If not specified, Travis use a system with ruby, which we don't need. We can use the "minimal" one instead.