css: Use SCSS nesting for `.top-links a` in portico.scss.
css: Use SCSS nesting for `.top-links a` in portico.scss.

punchagan/zulip,showell/zulip,hackerkid/zulip,rht/zulip,synicalsyntax/zulip,kou/zulip,eeshangarg/zulip,synicalsyntax/zulip,timabbott/zulip,rht/zulip,brainwane/zulip,zulip/zulip,eeshangarg/zulip,kou/zulip,rht/zulip,showell/zulip,hackerkid/zulip,zulip/zulip,showell/zulip,andersk/zulip,synicalsyntax/zulip,synicalsyntax/zulip,brainwane/zulip,andersk/zulip,shubhamdhama/zulip,synicalsyntax/zulip,timabbott/zulip,hackerkid/zulip,brainwane/zulip,shubhamdhama/zulip,punchagan/zulip,timabbott/zulip,shubhamdhama/zulip,eeshangarg/zulip,timabbott/zulip,rht/zulip,punchagan/zulip,kou/zulip,showell/zulip,synicalsyntax/zulip,rht/zulip,andersk/zulip,hackerkid/zulip,brainwane/zulip,eeshangarg/zulip,zulip/zulip,rht/zulip,hackerkid/zulip,andersk/zulip,timabbott/zulip,hackerkid/zulip,eeshangarg/zulip,shubhamdhama/zulip,shubhamdhama/zulip,kou/zulip,andersk/zulip,zulip/zulip,showell/zulip,eeshangarg/zulip,showell/zulip,hackerkid/zulip,timabbott/zulip,showell/zulip,punchagan/zulip,kou/zulip,synicalsyntax/zulip,brainwane/zulip,andersk/zulip,punchagan/zulip,brainwane/zulip,punchagan/zulip,brainwane/zulip,andersk/zulip,shubhamdhama/zulip,kou/zulip,punchagan/zulip,shubhamdhama/zulip,rht/zulip,eeshangarg/zulip,zulip/zulip,zulip/zulip,kou/zulip,zulip/zulip,timabbott/zulip