Update and improve script templating documentation [SPR-16447]

[spring-projects-issues]

Sébastien Deleuze opened SPR-16447 and commented

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Issue Links:

• [docs]: Add WebFlux content on view technology [SPR-16393] #20939 [docs]: Add WebFlux content on view technology
• Support i18n and nested template loading in ScriptTemplateView render function [SPR-15064] #19630 Support i18n and nested template loading in ScriptTemplateView render function