fix broken sharing services (#3794)
fix broken sharing services (#3794)

* changed the help link of movim from github to official website
* fixed missed help link of lemmy
* fixed missed link of mastodon
* reorder the share services - now ordered by alphabet
* extended the comments
Alkarex/FreshRSS,FreshRSS/FreshRSS,FreshRSS/FreshRSS,aledeg/FreshRSS,aledeg/FreshRSS,FreshRSS/FreshRSS,Alkarex/FreshRSS,FreshRSS/FreshRSS,aledeg/FreshRSS,aledeg/FreshRSS,Alkarex/FreshRSS,Alkarex/FreshRSS