fix several typos

[striezel]

Fixes typos in documentation / comments.

[striezel]

Some of the Ubuntu builds failed with the following error:

[100%] Built target checkperf
Test project /home/runner/work/simdjson/simdjson/build
    Start 86: checkperf
1/1 Test #86: checkperf ........................***Failed    0.28 sec
Attempt #1 of 7
/home/runner/work/simdjson/simdjson/build/benchmark/dom/parse -H -t /home/runner/work/simdjson/simdjson/build/jsonexamples/twitter.json
perf_event_open: Permission denied
[                                                  ]���������������������������������������������������=��                                                     �����������������������������������������������������New throughput: 1.8294
/home/runner/work/simdjson/simdjson/build/benchmark/dom/checkperf-reference/master/build/benchmark/parse -H -t /home/runner/work/simdjson/simdjson/build/jsonexamples/twitter.json
sh: 1: /home/runner/work/simdjson/simdjson/build/benchmark/dom/checkperf-reference/master/build/benchmark/parse: not found
Error 32512 running benchmark command!


Errors while running CTest
0% tests passed, 1 tests failed out of 1

Label Time Summary:
explicitonly          =   0.28 sec*proc (1 test)
per_implementation    =   0.28 sec*proc (1 test)

Total Test time (real) =   0.32 sec

The following tests FAILED:
	 86 - checkperf (Failed)
Error: Process completed with exit code 8.

I am not sure why that happens, but it seems the current master commit 85b910814eff8c21ccd055e4136b2931d9211d41 has the same problem with those two checks failing there, too. (See https://github.com/simdjson/simdjson/runs/2479665990 and https://github.com/simdjson/simdjson/runs/2479666044.) Therefore I assume it is not caused by some kind of regression introduced by this pull request.

[lemire]

I am happy to merge this. I will have a quick look at the perf check routine. It broke following another PR being merged.

[lemire]

Merged.