fix: correct some typos and grammatical problem

[BruceAko]

Details

Fix some typos and grammatical problem.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation Update (if none of the other choices apply)

Checklist

• I have updated the documentation accordingly.
• I have added tests to cover my changes.

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 6 lines in your changes missing coverage. Please review.

Project coverage is 61.52%. Comparing base (34ab06b) to head (11b16a8).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1578   +/-   ##
=======================================
  Coverage   61.51%   61.52%           
=======================================
  Files         144      144           
  Lines       46616    46616           
  Branches    44602    44602           
=======================================
+ Hits        28676    28680    +4     
+ Misses      16456    16452    -4     
  Partials     1484     1484           

Files	Coverage Δ
api/src/config.rs	87.58% <100.00%> (ø)
builder/src/merge.rs	70.79% <100.00%> (ø)
rafs/src/fs.rs	34.33% <ø> (ø)
rafs/src/metadata/mod.rs	70.45% <ø> (ø)
service/src/fs_service.rs	40.92% <ø> (ø)
src/bin/nydus-image/inspect.rs	0.00% <ø> (ø)
src/bin/nydus-image/main.rs	0.69% <ø> (ø)
src/bin/nydusd/api_server_glue.rs	0.00% <ø> (ø)
src/logger.rs	38.68% <ø> (ø)
storage/src/backend/mod.rs	56.07% <ø> (ø)
... and 14 more

... and 2 files with indirect coverage changes

[imeoer]

Thanks, LGTM!