[doc] "running" page fixes

[VladimirAlexiev]

I edited http://alphadoc.plantuml.com/doc/markdown/en/command-line to make a link:
(See [running](running) for ways to run PlantUML from various other tools and workflows),
hope this link works.

Now I'd like to edit https://plantuml.com/running but that page is not editable, probably because it has a special structure:

• change title from "Tools using the PlantUML language" to "Running PlantUML from Other Tools"
• change intro from "There are many ways of using PlantUML" to

PlantUML is integrated in a variety of external tools. 
See [command-line](command-line) for options to run it from the command line.