Split out lexicon, plugins and config page content

[mauriceyap]

In the documentation site, extract out the pre-templater content of the pages, lexicon.html, plugins.html and config.html into separate build targets, so that they can be used to build out a search index. In the search index, we do not want the content which the templater adds from template.html.

I have tested this by ensuring that these three generated templated pages before, and after these changes are the same:

$ cp $(plz build //docs:lexicon_html) tmp/lexicon_old.html
$ cp $(plz build //docs:config_html) tmp/config_old.html
$ cp $(plz build //docs:plugins_html) tmp/plugins_old.html

# Make the changes

$ cp $(plz build //docs:lexicon_html) tmp/lexicon_new.html
$ cp $(plz build //docs:config_html) tmp/config_new.html
$ cp $(plz build //docs:plugins_html) tmp/plugins_new.html

$ diff tmp/lexicon_old.html tmp/lexicon_new.html  # no output
$ diff tmp/config_old.html tmp/config_new.html # no output
$ diff tmp/plugins_old.html tmp/plugins_new.html # no output

[toastwaffle]

Why?

And more accurately, why not:

genrule(
    name = "lexicon_html",
    srcs = deps + [
        ":lexicon_content",
        "template.html",
    ],
    outs = ["lexicon.html"],
    cmd = [
        '"$TOOL" --template docs/template.html --in docs/lexicon_content.html > "$OUT"',
    ],
    tools = ["//docs/tools/templater"],
    visibility = ["//docs/test/..."],
)

similarly below.

I'm not a fan of how the command relies on filenames rather than using $SRCS, but I'm guessing the template implicitly depends on the files in deps, which makes it hard to use the dict-style srcs

[toastwaffle]

You removed deps in the other two _content targets?

[peterebden]

As I've mentioned on #3192 , I'm unclear that building a search index ourselves is the right approach to take. We should agree on the approach to take before making more code changes.