The new text is from the preceding two commits, 22123ab622 + ded1c8789b.

Fixes a broken link.

Fixes zsh-users/zsh-syntax-highlighting#235.

* phy1729/doc-all:
  Remove broken links
  docs: Create all.md
  docs: Move docs into docs/
  docs: Remove duplicate 'How to activate it' sections
  docs: Move highlighter headers down one level

* danielsh/docs-copyedit-v1:
  docs copyedit: minor: Spelling/punctuation fix.
  docs copyedit: Rewrap to 80 columns, part 4.
  docs copyedit: Rewrap to 80 columns, part 3.
  docs copyedit: Rewrap to 80 columns, part 2.
  docs copyedit: Clarify tagline.
  docs copyedit: minor.
  docs copyedit: Review toplevel and tests README.md files.
  docs copyedit: Rewrap to 80 columns.
  docs copyedit: Restyle bold-italic to fixed-width.
  docs copyedit: Port 6d93ea07fd to the other highlighters' README's.
  docs copyedit: Whitespace.

Restore zsh URL removed a few commits ago.

In particular, tests were relying on the harness to provide a sandbox working
directory, but the perf harness wasn't providing that.

At this time, no user-visible consequences are known.

Change quoting to only quote the shell variable, not the make variable.  This
allows the leading '~' to be unescaped for make's sh to expand.

Followup to b1619c0013.

Patch-by: Matthew Martin

- Install the top-level README.md, which wasn't installed before.
- Install docs to /usr/local/share/doc rather than /usr/local/share.

Done in c30301d474 and
c687bddea3 for other tests.

Fixes zsh-users/zsh-syntax-highlighting#101.

Followup to c015339202.

Suggested-by: Matthew Martin

Fixes zsh-users/zsh-syntax-highlighting#162.