run-mypy: Give CLI option help a consistent style.
run-mypy: Give CLI option help a consistent style.

Most CLI tools (including GNU tools and Mercurial) use lowercase
sentence fragments, with no period, for option glosses, so we
follow that style.  Also make the voice and wording consistent,
and the quote type in the Python source.

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