docs(15.9): the Groovy script plugin is no longer bundled

[marevol]

codelibs/fess#3425 stopped fetching fess-script-groovy at prepare-package and shipping it in WEB-INF/plugin, so 15.9 itself is the release where the plugin has to be installed.

Two pages in the 15.9 tree still described the plan that PR replaced:

Page	What it said
config/scripting-groovy.rst	"It is bundled with the 15.9 distribution, so it works out of the box, but starting with 15.10 the plugin will no longer be bundled"
config/scripting-overview.rst	the same claim, in the scripting-language table

Both halves are wrong now: an installation that upgrades to 15.9 and does nothing loses Groovy, and there is no 15.10 transition left to prepare for.

Both pages now say the plugin is not part of the distribution and name the two ways to install it — the System > Plugin page in the admin UI, and bin/fess-setup install plugin fess-script-groovy, which is the exact form FessSetup prints in its own usage error. The manual-install example moves from fess-script-groovy-15.10.0.jar to 15.9.0.jar for the same reason.

What did not need changing

The eight other pages in the 15.9 tree that name the plugin already phrase it as "requires the fess-script-groovy plugin", and install/upgrade.rst already described the 15.9 behaviour correctly. Nothing outside the 15.9 development tree was touched.

Verification

Seven languages, two files each. Each file was parsed with docutils before and after the edit using doctitle_xform=False, the way Sphinx parses, and the two results compared:

• no new system messages
• no bold or literal markup left unparsed in the rendered text

The second check is the one that matters here, because docutils requires whitespace or punctuation around an inline start-string and fails silently when a CJK character sits directly against it. It was confirmed to be a real check rather than a vacuous one by feeding it a known-broken text**bold**more, which it flags.