templates: Add links to user docs for empty starred/mentioned msg feeds.
templates: Add links to user docs for empty starred/mentioned msg feeds.

Fixes #6376

hackerkid/zulip,punchagan/zulip,timabbott/zulip,jackrzhang/zulip,brockwhittaker/zulip,kou/zulip,rht/zulip,rishig/zulip,verma-varsha/zulip,timabbott/zulip,dhcrzf/zulip,hackerkid/zulip,hackerkid/zulip,tommyip/zulip,showell/zulip,showell/zulip,synicalsyntax/zulip,dhcrzf/zulip,showell/zulip,jackrzhang/zulip,shubhamdhama/zulip,amanharitsh123/zulip,amanharitsh123/zulip,rishig/zulip,eeshangarg/zulip,punchagan/zulip,punchagan/zulip,mahim97/zulip,mahim97/zulip,rht/zulip,Galexrt/zulip,mahim97/zulip,hackerkid/zulip,verma-varsha/zulip,tommyip/zulip,dhcrzf/zulip,verma-varsha/zulip,hackerkid/zulip,verma-varsha/zulip,amanharitsh123/zulip,showell/zulip,tommyip/zulip,kou/zulip,timabbott/zulip,zulip/zulip,andersk/zulip,Galexrt/zulip,Galexrt/zulip,eeshangarg/zulip,eeshangarg/zulip,andersk/zulip,eeshangarg/zulip,shubhamdhama/zulip,timabbott/zulip,dhcrzf/zulip,shubhamdhama/zulip,tommyip/zulip,dhcrzf/zulip,tommyip/zulip,rht/zulip,kou/zulip,kou/zulip,timabbott/zulip,Galexrt/zulip,brainwane/zulip,shubhamdhama/zulip,zulip/zulip,shubhamdhama/zulip,rishig/zulip,synicalsyntax/zulip,synicalsyntax/zulip,showell/zulip,Galexrt/zulip,verma-varsha/zulip,andersk/zulip,punchagan/zulip,punchagan/zulip,rishig/zulip,rishig/zulip,punchagan/zulip,amanharitsh123/zulip,eeshangarg/zulip,brockwhittaker/zulip,timabbott/zulip,tommyip/zulip,synicalsyntax/zulip,andersk/zulip,synicalsyntax/zulip,showell/zulip,hackerkid/zulip,dhcrzf/zulip,andersk/zulip,jackrzhang/zulip,Galexrt/zulip,brainwane/zulip,shubhamdhama/zulip,synicalsyntax/zulip,rishig/zulip,brockwhittaker/zulip,amanharitsh123/zulip,tommyip/zulip,brainwane/zulip,shubhamdhama/zulip,showell/zulip,zulip/zulip,brockwhittaker/zulip,brainwane/zulip,mahim97/zulip,jackrzhang/zulip,kou/zulip,zulip/zulip,kou/zulip,brainwane/zulip,dhcrzf/zulip,rishig/zulip,timabbott/zulip,mahim97/zulip,jackrzhang/zulip,jackrzhang/zulip,kou/zulip,hackerkid/zulip,rht/zulip,Galexrt/zulip,verma-varsha/zulip,mahim97/zulip,brockwhittaker/zulip,zulip/zulip,brainwane/zulip,eeshangarg/zulip,andersk/zulip,eeshangarg/zulip,rht/zulip,rht/zulip,brockwhittaker/zulip,rht/zulip,zulip/zulip,brainwane/zulip,andersk/zulip,synicalsyntax/zulip,jackrzhang/zulip,amanharitsh123/zulip,zulip/zulip,punchagan/zulip