docs: fix typos and wording in learn and README docs

[maradini77]

Description

Closes: #XXXX

This PR fixes minor documentation issues across several README and learn pages:

• Corrects spelling, capitalization, and grammar (e.g. brand names, prepositions, inequality symbols).
• Fixes small formatting issues and broken/incorrect markdown links in the learn docs.
• Improves a few sentences for clarity without changing their technical meaning.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.63%. Comparing base (a15ac0b) to head (a5ede3a).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #25668      +/-   ##
==========================================
+ Coverage   68.50%   70.63%   +2.13%     
==========================================
  Files         865      830      -35     
  Lines       56145    54058    -2087     
==========================================
- Hits        38460    38186     -274     
+ Misses      17685    15872    -1813     

Files with missing lines	Coverage Δ
blockstm/utils.go	90.00% <ø> (ø)
x/bank/keeper/virtual.go	77.22% <ø> (ø)

... and 39 files with indirect coverage changes

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[ericHgorski]

LGTM