minor: Change wording in comment to avoid "subject".
minor: Change wording in comment to avoid "subject".

We're trying to sweep "subject" out of the codebase,
even when it has nothing to do our legacy "subject"
field.  The rewording here will prevent some linter
noise.

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