docs: Add godocs to GasMeter methods

[likhita-809]

Description

ref: #9651

This is a follow-up PR of adding godocs to GasMeter methods

---

Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• followed the guidelines for building modules
• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
• reviewed "Files changed" and left comments if necessary
• confirmed all CI checks have passed

Reviewers Checklist

All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.

I have...

• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[codecov]

Codecov Report

Merging #9665 (bfa7536) into master (0027111) will increase coverage by 27.91%.
The diff coverage is 63.61%.

❗ Current head bfa7536 differs from pull request most recent head 61ca6e3. Consider uploading reports for the commit 61ca6e3 to get more accurate results

@@             Coverage Diff             @@
##           master    #9665       +/-   ##
===========================================
+ Coverage   35.48%   63.40%   +27.91%     
===========================================
  Files         332      572      +240     
  Lines       32620    37555     +4935     
===========================================
+ Hits        11575    23810    +12235     
+ Misses      19819    11887     -7932     
- Partials     1226     1858      +632     

Impacted Files	Coverage Δ
client/keys/types.go	100.00% <ø> (+100.00%)	⬆️
client/query.go	16.98% <ø> (ø)
client/rpc/block.go	0.00% <ø> (ø)
client/rpc/status.go	67.74% <ø> (ø)
client/rpc/validators.go	0.00% <ø> (ø)
client/test_helpers.go	0.00% <ø> (ø)
client/tx/factory.go	27.00% <ø> (ø)
client/tx/legacy.go	68.42% <ø> (ø)
client/tx/tx.go	40.83% <ø> (ø)
client/utils.go	41.93% <ø> (-41.40%)	⬇️
... and 682 more

[ruhatch]

Nice, thanks - I guess waiting on response to your question!