docs: replace links to Cosmos's repository with ours

[loloicci]

Description

Replace links to original codes with ours.

---

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests (Not Needed)
• Updated relevant documentation (docs/) or specification (x/<module>/spec/) (Not Needed)
• Added relevant godoc comments. (Not Needed)
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer
• Review Codecov Report in the comment section below once CI passes

[loloicci]

Test fails about gas in x/wasm/internal/keeper/keeper_test.go. This is not edited in this PR.
Sorry, this is because a parameter of Create is changed. I will fix it in the next patch.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (main@3ccf391). Click here to learn what that means.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #245   +/-   ##
=======================================
  Coverage        ?   53.64%           
=======================================
  Files           ?      652           
  Lines           ?    47368           
  Branches        ?        0           
=======================================
  Hits            ?    25410           
  Misses          ?    19097           
  Partials        ?     2861