DOCS: IMDG Reference Manual: Minor improvement propositions for intro page - Support chapter

https://github.com/hazelcast/imdg-docs/blob/master/docs/modules/ROOT/pages/index.adoc

1. Community support is for every Hazelcast IMDG user. - > I would change to “Community support is available for every HZ IMDG user”
2. You can use the following channels for this purpose - > Apologies, I’m a bit confused with “purpose” word, could it be something like “Following channels are available for community support:”
3. Hazelcast GitHub (for reporting issues through our GitHub repository) - > from my narrow perspective, should be changed to “Reporting issues on Hazelcast GitHub”
4. StackOverflow - > It is a direct link to SO, which is a bit confusing. It’s better to show link to HZ search https://stackoverflow.com/questions/tagged/hazelcast - it will open HZ questions.
5. Customer support is for the paying Hazelcast IMDG customers - > I think more polite way is to use “premium customer”, not paying
6. Customer support is for the paying Hazelcast IMDG customers - > If 2 is adressed, this could be changed to “Customer support is available for premium customers only”
7. See hazelcast.com for the support options. -> We are describing support options here, hence, I would propose to change to See .. for more information.