fixed typos in waspc/docs/wasplang/src/index.tex

[parikshitadhikari]

Description

Typos in index.tex inside the directory waspc/docs.wasplang/src/index.tex has been fixed.

Select what type of change this PR introduces:

1. Just code/docs improvement (no functional change).
2. Bug fix (non-breaking change which fixes an issue).
3. New feature (non-breaking change which adds functionality).
4. Breaking change (fix or feature that would cause existing functionality to not work as expected).

Update Waspc ChangeLog and version if needed

If you did a bug fix, new feature, or breaking change, that affects waspc, make sure you satisfy the following:

1. I updated ChangeLog.md with description of the change this PR introduces.
2. I bumped waspc version in waspc.cabal to reflect changes I introduced, with regards to the version of the latest wasp release, if the bump was needed.

[infomiho]

Thank you for the contribution