[charts][docs] Correct some small grammar mistakes

[mapache-salvaje]

experimenting with LLMs for copyediting

[mui-bot]

Deploy preview: https://deploy-preview-19297--material-ui-x.netlify.app/

Updated pages:

• docs/data/charts/areas-demo/areas-demo.md
• docs/data/charts/axis/axis.md
• docs/data/charts/bar-demo/bar-demo.md
• docs/data/charts/bars/bars.md
• docs/data/charts/components/components.md

Bundle size report

Bundle	Parsed size	Gzip size
@mui/x-data-grid	0B(0.00%)	0B(0.00%)
@mui/x-data-grid-pro	0B(0.00%)	0B(0.00%)
@mui/x-data-grid-premium	0B(0.00%)	0B(0.00%)
@mui/x-charts	0B(0.00%)	0B(0.00%)
@mui/x-charts-pro	0B(0.00%)	0B(0.00%)
@mui/x-date-pickers	0B(0.00%)	0B(0.00%)
@mui/x-date-pickers-pro	0B(0.00%)	0B(0.00%)
@mui/x-tree-view	0B(0.00%)	0B(0.00%)
@mui/x-tree-view-pro	0B(0.00%)	0B(0.00%)

Details of bundle changes

Generated by 🚫 dangerJS against e9b90e7

[codspeed-hq]

CodSpeed Performance Report

Merging #19297 will not alter performance

_{Comparing mapache-salvaje:charts-grammar (e9b90e7) with master (ce8e44c)¹}

Summary

✅ 10 untouched benchmarks

Footnotes

1. No successful run was found on master (4bedded) during the generation of this report, so ce8e44c was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩