markdown preview: Fix `code` style for preview in night mode.
markdown preview: Fix `code` style for preview in night mode.

When in night mode, `code` style was still the same as in the light mode;
The fix is for the same.

Fixes #11269.

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