[ImgBot] Optimize images in documentation (select2#6202)

*Total -- 1,717.61kb -> 1,463.41kb (14.8%)

/docs/pages/images/flags/wa.png -- 44.19kb -> 7.72kb (82.53%)
/docs/pages/images/flags/wv.png -- 44.19kb -> 12.03kb (72.78%)
/docs/pages/images/flags/hi.png -- 3.10kb -> 1.47kb (52.59%)
/docs/pages/images/flags/sc.png -- 4.38kb -> 2.27kb (48.16%)
/docs/themes/learn2/images/favicon.png -- 1.15kb -> 0.72kb (37.72%)
/docs/pages/images/flags/al.png -- 2.56kb -> 1.68kb (34.39%)
/docs/plugins/error/assets/readme_1.png -- 40.71kb -> 28.36kb (30.33%)
/docs/pages/images/flags/ak.png -- 2.16kb -> 1.59kb (26.18%)
/docs/themes/learn2/images/logo.png -- 1.19kb -> 0.88kb (26.01%)
/docs/themes/site/images/safari-pinned-tab.svg -- 0.75kb -> 0.56kb (25.42%)
/docs/plugins/problems/assets/readme_1.png -- 71.20kb -> 53.70kb (24.58%)
/docs/pages/images/flags/ms.png -- 5.95kb -> 4.54kb (23.6%)
/docs/pages/images/flags/ar.png -- 10.62kb -> 8.11kb (23.59%)
/docs/plugins/simplesearch/assets/search.svg -- 0.95kb -> 0.74kb (22.22%)
/docs/plugins/highlight/assets/readme_1.png -- 163.69kb -> 127.78kb (21.94%)
/docs/pages/images/flags/nm.png -- 1.49kb -> 1.17kb (21.08%)
/docs/pages/images/flags/in.png -- 6.82kb -> 5.43kb (20.49%)
/docs/pages/images/flags/az.png -- 5.32kb -> 4.25kb (20.19%)
/docs/pages/images/flags/tx.png -- 1.29kb -> 1.04kb (19.64%)
/docs/pages/images/flags/ri.png -- 6.76kb -> 5.45kb (19.49%)
/docs/pages/images/flags/tn.png -- 3.91kb -> 3.16kb (19.2%)
/docs/plugins/breadcrumbs/assets/readme_1.png -- 60.44kb -> 48.90kb (19.09%)
/docs/assets/rtfm-screenshot.png -- 131.33kb -> 107.16kb (18.41%)
/docs/pages/images/flags/oh.png -- 7.49kb -> 6.28kb (16.06%)
/docs/pages/images/flags/co.png -- 2.53kb -> 2.18kb (14.08%)
/docs/screenshot.jpg -- 147.13kb -> 127.14kb (13.59%)
/docs/themes/learn2/screenshot.jpg -- 118.97kb -> 102.90kb (13.5%)
/docs/pages/images/flags/md.png -- 4.01kb -> 3.47kb (13.38%)
/docs/pages/images/flags/ga.png -- 4.65kb -> 4.05kb (12.89%)
/docs/pages/images/flags/ca.png -- 6.99kb -> 6.10kb (12.8%)
/docs/pages/images/flags/wy.png -- 4.24kb -> 3.74kb (11.81%)
/docs/pages/images/flags/sd.png -- 10.01kb -> 8.89kb (11.24%)
/docs/pages/images/flags/la.png -- 11.22kb -> 10.01kb (10.8%)
/docs/pages/images/flags/ne.png -- 13.57kb -> 12.15kb (10.45%)
/docs/pages/images/flags/or.png -- 9.31kb -> 8.40kb (9.79%)
/docs/pages/images/flags/nc.png -- 3.90kb -> 3.57kb (8.46%)
/docs/pages/images/flags/de.png -- 7.72kb -> 7.12kb (7.81%)
/docs/pages/images/flags/nv.png -- 4.17kb -> 3.85kb (7.69%)
/docs/pages/images/flags/pa.png -- 10.93kb -> 10.10kb (7.62%)
/docs/pages/images/flags/mo.png -- 7.32kb -> 6.77kb (7.54%)
/docs/pages/images/flags/ky.png -- 9.92kb -> 9.19kb (7.41%)
/docs/pages/images/flags/mn.png -- 7.75kb -> 7.20kb (7.11%)
/docs/pages/images/flags/ia.png -- 6.94kb -> 6.46kb (6.83%)
/docs/themes/learn2/thumbnail.jpg -- 20.52kb -> 19.19kb (6.48%)
/docs/pages/images/flags/ut.png -- 10.42kb -> 9.77kb (6.3%)
/docs/pages/images/flags/ct.png -- 8.99kb -> 8.43kb (6.29%)
/docs/pages/images/flags/nh.png -- 12.49kb -> 11.74kb (6%)
/docs/pages/images/flags/fl.png -- 8.81kb -> 8.33kb (5.4%)
/docs/pages/images/flags/mi.png -- 10.23kb -> 9.73kb (4.86%)
/docs/pages/images/flags/ok.png -- 7.12kb -> 6.81kb (4.4%)
/docs/pages/images/flags/nd.png -- 11.52kb -> 11.01kb (4.38%)
/docs/pages/images/flags/va.png -- 9.90kb -> 9.47kb (4.37%)
/docs/plugins/simplesearch/assets/readme_1.png -- 110.46kb -> 106.12kb (3.93%)
/docs/pages/images/flags/wi.png -- 8.34kb -> 8.08kb (3.12%)
/docs/pages/images/flags/ks.png -- 7.58kb -> 7.35kb (2.99%)
/docs/pages/images/flags/ma.png -- 3.89kb -> 3.78kb (2.96%)
/docs/pages/images/flags/mt.png -- 7.17kb -> 7.00kb (2.46%)
/docs/pages/images/flags/vt.png -- 6.25kb -> 6.09kb (2.45%)
/docs/themes/learn2/fonts/fontawesome-webfont.svg -- 433.96kb -> 425.36kb (1.98%)
/docs/themes/learn2/images/clippy.svg -- 0.51kb -> 0.50kb (1.16%)
/docs/pages/images/flags/il.png -- 10.11kb -> 10.05kb (0.63%)
/docs/pages/images/flags/ny.png -- 9.50kb -> 9.45kb (0.53%)
/docs/pages/images/flags/nj.png -- 6.93kb -> 6.92kb (0.21%)

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