Load independent and minimal syntax sets when using --language (#1787)

This significantly speeds up the startup time of bat, since only a single
linked SyntaxDefinition is loaded for each file. The size increase of the
binary is just ~400 kB.

In order for startup time to be improved, the --language arg must be used, and
it must match one of the following names:

"Plain Text", "ActionScript", "AppleScript", "Batch File", "NAnt Build File",
"C#", "C", "CSS", "D", "Diff", "Erlang", "Go", "Haskell", "JSON", "Java
Properties", "BibTeX", "LaTeX Log", "TeX", "Lisp", "Lua", "MATLAB", "Pascal",
"R", "Regular Expression", "Rust", "SQL", "Scala", "Tcl", "XML", "YAML", "Apache
Conf", "ARM Assembly", "Assembly (x86_64)", "CMakeCache", "Comma Separated
Values", "Cabal", "CoffeeScript", "CpuInfo", "Dart Analysis Output", "Dart",
"Dockerfile", "DotENV", "F#", "Friendly Interactive Shell (fish)", "Fortran
(Fixed Form)", "Fortran (Modern)", "Fortran Namelist", "fstab", "GLSL",
"GraphQL", "Groff/troff", "group", "hosts", "INI", "Jinja2", "jsonnet",
"Kotlin", "Less", "LLVM", "Lean", "MemInfo", "Nim", "Ninja", "Nix", "passwd",
"PowerShell", "Protocol Buffer (TEXT)", "Puppet", "Rego", "resolv", "Robot
Framework", "SML", "Strace", "Stylus", "Solidity", "Vyper", "Swift",
"SystemVerilog", "TOML", "Terraform", "TypeScript", "TypeScriptReact",
"Verilog", "VimL", "Zig", "gnuplot", "log", "requirements.txt", "Highlight
non-printables", "Private Key", "varlink"

Later commits will improve startup time for more code paths.

* fix some typos and misspellings

* CHANGELOG.md: Add Performance section (preliminary)

* Add a CHANGELOG.md entry for this PR

src/bin/bat/assets.rs

@@ -20,6 +20,7 @@ pub fn cache_dir() -> Cow<'static, str> {
 pub fn clear_assets() {
     clear_asset("themes.bin", "theme set cache");
     clear_asset("syntaxes.bin", "syntax set cache");
+    clear_asset("minimal_syntaxes.bin", "minimal syntax sets cache");
     clear_asset("metadata.yaml", "metadata file");
 }