fix some javadoc comments

[lukairui]

Ⅰ. Describe what this PR did

    Some adjustments on the comments.

Ⅱ. Does this pull request fix one issue?

    No.

Ⅲ. Why don't you add test cases (unit test/integration test)?

    That is not necessary.

Ⅳ. Describe how to verify it

    em.....

Ⅴ. Special notes for reviews

    Nothing.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (develop@ab6bece). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             develop   #1416   +/-   ##
=========================================
  Coverage           ?   45.5%           
  Complexity         ?    1661           
=========================================
  Files              ?     345           
  Lines              ?   12666           
  Branches           ?    1598           
=========================================
  Hits               ?    5764           
  Misses             ?    6252           
  Partials           ?     650

Impacted Files	Coverage Δ	Complexity Δ
...e/src/main/java/io/seata/core/store/StoreMode.java	0% <ø> (ø)	0 <0> (?)
.../src/main/java/io/seata/core/constants/DBType.java	73.33% <ø> (ø)	1 <0> (?)
...ain/java/io/seata/core/store/db/LockStoreSqls.java	25% <ø> (ø)	3 <0> (?)
core/src/main/java/io/seata/core/lock/RowLock.java	0% <ø> (ø)	0 <0> (?)
core/src/main/java/io/seata/core/store/LockDO.java	95.83% <ø> (ø)	15 <0> (?)
.../java/io/seata/core/store/BranchTransactionDO.java	92.3% <ø> (ø)	23 <0> (?)
.../main/java/io/seata/core/protocol/MessageType.java	0% <ø> (ø)	0 <0> (?)
...main/java/io/seata/core/store/db/LogStoreSqls.java	23.25% <ø> (ø)	10 <0> (?)
...ata/core/store/db/AbstractDataSourceGenerator.java	0% <ø> (ø)	0 <0> (?)
.../java/io/seata/core/store/GlobalTransactionDO.java	97.14% <ø> (ø)	23 <0> (?)
... and 6 more

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[slievrly]

LGTM