[DOCS] Plugin Installation for Windows (#21671)

This shows an example of how to install a plugin on Windows, which is not as obvious at I would have expected.

docs/plugins/plugin-script.asciidoc

@@ -64,20 +64,40 @@ sudo bin/elasticsearch-plugin install [url] <1>
 -----------------------------------
 <1> must be a valid URL, the plugin name is determined from its descriptor.
 
-For instance, to install a plugin from your local file system, you could run:
+Unix::
-
++
+To install a plugin from your local file system at `/path/to/plugin.zip`, you could run:
++
 [source,shell]
 -----------------------------------
 sudo bin/elasticsearch-plugin install file:///path/to/plugin.zip
 -----------------------------------
 
+Windows::
++
+To install a plugin from your local file system at `C:\path\to\plugin.zip`, you could run:
++
+[source,shell]
+-----------------------------------
+bin\elasticsearch-plugin install file:///C:/path/to/plugin.zip
+-----------------------------------
++
+NOTE: Any path that contains spaces must be wrapped in quotes! 
+
+HTTP::
++
+[source,shell]
+-----------------------------------
+sudo bin/elasticsearch-plugin install http://some.domain/path/to/plugin.zip
+-----------------------------------
++
 The plugin script will refuse to talk to an HTTPS URL with an untrusted
 certificate. To use a self-signed HTTPS cert, you will need to add the CA cert
 to a local Java truststore and pass the location to the script as follows:
-
++
 [source,shell]
 -----------------------------------
-sudo ES_JAVA_OPTS="-Djavax.net.ssl.trustStore=/path/to/trustStore.jks" bin/elasticsearch-plugin install https://....
+sudo ES_JAVA_OPTS="-Djavax.net.ssl.trustStore=/path/to/trustStore.jks" bin/elasticsearch-plugin install https://host/plugin.zip
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