[ImgBot] Optimize images

*Total -- 250.33kb -> 226.67kb (9.45%)

/src/tools/rust-analyzer/assets/logo-square.svg -- 4.90kb -> 3.25kb (33.59%)
/tests/ui/diagnostic-flags/colored-session-opt-error.svg -- 0.80kb -> 0.58kb (26.68%)
/src/doc/rustc-dev-guide/src/mir/mir_overview.svg -- 5.20kb -> 4.23kb (18.64%)
/src/tools/rust-analyzer/assets/logo-wide.svg -- 12.87kb -> 10.73kb (16.63%)
/src/doc/rustc-dev-guide/src/mir/mir_detailed.svg -- 17.49kb -> 14.67kb (16.12%)
/src/librustdoc/html/static/images/rust-logo.svg -- 3.22kb -> 2.83kb (12.1%)
/tests/ui/error-emitter/E0308-clarification.svg -- 6.69kb -> 5.92kb (11.4%)
/tests/ui/error-emitter/highlighting.windows.svg -- 4.66kb -> 4.24kb (9.1%)
/tests/ui/error-emitter/highlighting.svg -- 4.56kb -> 4.15kb (9.03%)
/tests/ui/error-emitter/unicode-output.svg -- 4.65kb -> 4.24kb (8.86%)
/src/librustdoc/html/static/images/favicon.svg -- 4.20kb -> 3.84kb (8.54%)
/tests/ui/codemap_tests/huge_multispan_highlight.ascii.svg -- 7.82kb -> 7.18kb (8.15%)
/src/doc/rustc-dev-guide/src/mir/mir_cfg.svg -- 19.13kb -> 17.63kb (7.8%)
/tests/ui/codemap_tests/huge_multispan_highlight.unicode.svg -- 8.21kb -> 7.57kb (7.8%)
/tests/ui/error-emitter/multiline-removal-suggestion.svg -- 46.04kb -> 42.60kb (7.48%)
/tests/ui/error-emitter/multiline-multipart-suggestion.svg -- 8.95kb -> 8.32kb (7.08%)
/tests/ui/error-emitter/multiline-multipart-suggestion.windows.svg -- 9.07kb -> 8.44kb (6.99%)
/tests/ui/suggestions/incorrect-variant-literal.svg -- 81.87kb -> 76.24kb (6.88%)

Signed-off-by: ImgBotApp <[email protected]>

Author: ImgBotApp