Add & update Sinhala README

[dinithija]

What's in this PR?

Added sinhalese / sinhala readme for understand & read easily.

First come and first take, i like to acquire remaining space in the language line :)

Member of @HelaBasa unit, Nawala.

[codecov]

Codecov Report

Merging #1958 (21147c9) into dev (74e82b9) will not change coverage.
The diff coverage is n/a.

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  Hits          2064      2064           

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[jw-foss]

@dinithija Would you mind changing the title of this PR to something more specific:

"Add new language entry and README for Sinhala"

It would be much nicer for us to track the PR.

[dinithija]

@jw-foss This's a basic docs related PR, you can merge right now. e.g. similar to Add Turkish README #1840
And why @iamkun seems not active? Edit: I saw you've manager role, can you enable sinhala (si) language on https://crowdin.com/project/element-plus

[jw-foss]

I left a comment for you to consider, let me know if you have any questions

[dinithija]

I left a comment for you to consider, let me know if you have any questions

Sorry, that's a mistake. fixed

[iamkun]

🎉 This PR is included in version 1.11.4 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀