Bump version to 0.9.3 + update changelog (#121)

v0.9.2: tstyles uninstall says what it could not remove

A patch release for tstyles uninstall. On Windows PowerShell 5.1
without PSResourceGet it removes a Gallery copy, with Uninstall-Module
-AllVersions, where it used to call a command that is not there and
leave the module installed. Its sign-off says "TerminalStyles
uninstalled." only when nothing is left: a module copy -- on Windows,
in either engine's per-user module folder -- an install file, the
WezTerm module or part of the data folder that it could not remove is
named at the end with what finishes the job. SECURITY.md's supported
series stays 0.9.x.

v0.9.1: Gallery installs are told when a new release is out

v0.9.0: styles stick in VS Code's terminal

The fourth config writer: a style applied in VS Code, Insiders, VSCodium,
Cursor or Windsurf is written into that editor's settings.json after one
question per editor, with an undo record that reset, tstyles vscode off
and uninstall take it back out by. A minor bump, as 0.8.0 was for the
macOS and Linux support, since this is a new writer rather than a fix.
SECURITY.md now names 0.9.x as the supported series.

v0.8.46: shell scripts staged as LF

v0.8.45: phosphor, and two backgrounds that stop being scaled up

v0.8.44: skyline

v0.8.43: koholint fills the window