fix(docs): clean up npm uninstall docs

[wraithgar]

Lots of flags removed, clarification on what --no-save does,
consolidated examples into a separate section

References

Closes npm/statusboard#252

[npm-deploy-user]

found 2 benchmarks with statistically significant performance improvements

• app-large: no-clean:audit
• app-medium: cache-only

timing results

app-large	clean	lock-only	cache-only	cache-only legacy-peer-deps	modules-only	no-lock	no-cache	no-modules	no-clean	no-clean audit
npm@7	46.568 ±2.13	27.724 ±0.02	32.024 ±4.26	31.159 ±1.49	2.193 ±0.03	2.254 ±0.06	1.539 ±0.01	11.879 ±0.17	1.540 ±0.06	4.489 ±0.20
#2464	46.682 ±0.19	27.749 ±0.33	30.096 ±0.01	28.670 ±1.36	2.219 ±0.01	2.171 ±0.04	1.580 ±0.07	11.991 ±0.20	1.559 ±0.05	3.584 ±0.28

app-medium	clean	lock-only	cache-only	cache-only legacy-peer-deps	modules-only	no-lock	no-cache	no-modules	no-clean	no-clean audit
npm@7	33.636 ±1.77	19.497 ±0.16	24.362 ±2.31	19.406 ±1.74	2.103 ±0.02	2.116 ±0.03	1.437 ±0.01	7.490 ±0.07	1.441 ±0.05	2.731 ±0.15
#2464	34.190 ±0.31	19.608 ±0.38	21.113 ±0.36	20.658 ±0.15	2.106 ±0.02	2.139 ±0.07	1.464 ±0.04	7.501 ±0.15	1.461 ±0.04	2.779 ±0.19

[ljharb]

LGTM!

[darcyclarke]

Try to delineate a package's name (suggested code but maybe bold)