feat: lsp completion for internal pkg from program root

[He1pa]

1. Does this PR affect any open issues?(Y/N) and add issue references (e.g. "fix #123", "re #123".):

• N
• Y [Enhancement] Enhance the completion experience of KCL Import for both internal and external packages #1429

2. What is the scope of this PR (e.g. component or file name):

kclvm/tools/src/LSP/src/completion.rs

3. Provide a description of the PR(e.g. more details, effects, motivations or doc link):

lsp completion for internal pkg from program root

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Other

4. Are there any breaking changes?(Y/N) and describe the breaking changes(e.g. more details, motivations or doc link):

• N
• Y

5. Are there test cases for these changes?(Y/N) select and add more details, references or doc links:

• Unit test
• Integration test
• Benchmark (add benchmark stats below)
• Manual test (add detailed scripts or steps below)
• Other

[coveralls]

Pull Request Test Coverage Report for Build 9679474748

Details

• 55 of 69 (79.71%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.007%) to 71.44%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
kclvm/tools/src/LSP/src/completion.rs	55	69	79.71%

Totals
Change from base Build 9678513942:	0.007%
Covered Lines:	55879
Relevant Lines:	78218

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💛 - Coveralls