user docs: Fix broken link to enable-enter-to-send.
user docs: Fix broken link to enable-enter-to-send.

Fixes regression from 976b560.

rht/zulip,jackrzhang/zulip,tommyip/zulip,jackrzhang/zulip,shubhamdhama/zulip,dhcrzf/zulip,showell/zulip,hackerkid/zulip,hackerkid/zulip,eeshangarg/zulip,zulip/zulip,showell/zulip,timabbott/zulip,shubhamdhama/zulip,hackerkid/zulip,synicalsyntax/zulip,hackerkid/zulip,eeshangarg/zulip,tommyip/zulip,tommyip/zulip,tommyip/zulip,eeshangarg/zulip,brainwane/zulip,synicalsyntax/zulip,shubhamdhama/zulip,kou/zulip,rishig/zulip,kou/zulip,rht/zulip,shubhamdhama/zulip,dhcrzf/zulip,punchagan/zulip,timabbott/zulip,jackrzhang/zulip,andersk/zulip,rishig/zulip,rht/zulip,rht/zulip,jackrzhang/zulip,zulip/zulip,jackrzhang/zulip,zulip/zulip,rht/zulip,kou/zulip,punchagan/zulip,andersk/zulip,rishig/zulip,brainwane/zulip,tommyip/zulip,andersk/zulip,punchagan/zulip,rishig/zulip,shubhamdhama/zulip,jackrzhang/zulip,synicalsyntax/zulip,shubhamdhama/zulip,timabbott/zulip,punchagan/zulip,brainwane/zulip,eeshangarg/zulip,rishig/zulip,kou/zulip,kou/zulip,synicalsyntax/zulip,synicalsyntax/zulip,brainwane/zulip,hackerkid/zulip,punchagan/zulip,andersk/zulip,rht/zulip,eeshangarg/zulip,jackrzhang/zulip,timabbott/zulip,zulip/zulip,eeshangarg/zulip,brainwane/zulip,andersk/zulip,tommyip/zulip,kou/zulip,timabbott/zulip,shubhamdhama/zulip,kou/zulip,showell/zulip,timabbott/zulip,eeshangarg/zulip,andersk/zulip,dhcrzf/zulip,punchagan/zulip,zulip/zulip,rishig/zulip,hackerkid/zulip,zulip/zulip,brainwane/zulip,dhcrzf/zulip,dhcrzf/zulip,hackerkid/zulip,punchagan/zulip,brainwane/zulip,timabbott/zulip,rishig/zulip,showell/zulip,synicalsyntax/zulip,tommyip/zulip,showell/zulip,dhcrzf/zulip,rht/zulip,showell/zulip,zulip/zulip,showell/zulip,andersk/zulip,synicalsyntax/zulip,dhcrzf/zulip