fix(base-account): remove dangling code fences in provider RPC reference docs

[vhtgzzl]

Summary

This PR resolves syntax defects and formatting anomalies across the Base Account Provider RPC methods reference documentation (docs/base-account/reference/core/provider-rpc-methods/):

1. Remove Trailing Unclosed Code Fences:

   • Fixed unclosed / empty ``` code fences left at the end of 6 RPC method MDX reference pages (eth_getBlockTransactionCountByHash.mdx, eth_getStorageAt.mdx, eth_getUncleCountByBlockHash.mdx, eth_getUncleCountByBlockNumber.mdx, eth_getTransactionByBlockHashAndIndex.mdx, eth_getTransactionByBlockNumberAndIndex.mdx).
   • Prevents MDX parser errors and broken document layouts in Mintlify.

2. Add Missing Frontmatter Description:

   • Added descriptive description property to request-overview.mdx frontmatter to comply with Mintlify metadata standards.

Changes Made

• docs/base-account/reference/core/provider-rpc-methods/eth_getBlockTransactionCountByHash.mdx: Removed trailing dangling code fence.
• docs/base-account/reference/core/provider-rpc-methods/eth_getStorageAt.mdx: Removed trailing dangling code fence.
• docs/base-account/reference/core/provider-rpc-methods/eth_getUncleCountByBlockHash.mdx: Removed trailing dangling code fence.
• docs/base-account/reference/core/provider-rpc-methods/eth_getUncleCountByBlockNumber.mdx: Removed trailing dangling code fence.
• docs/base-account/reference/core/provider-rpc-methods/eth_getTransactionByBlockHashAndIndex.mdx: Removed 2 trailing empty code fences.
• docs/base-account/reference/core/provider-rpc-methods/eth_getTransactionByBlockNumberAndIndex.mdx: Removed 2 trailing empty code fences.
• docs/base-account/reference/core/provider-rpc-methods/request-overview.mdx: Added description frontmatter metadata.

Verification

• Audited all 492 MDX/MD files in docs/ to confirm zero remaining unmatched code fences.
• Verified that all Mintlify components (<Info>, <ParamField>, <ResponseField>, <RequestExample>, <ResponseExample>) and JSX tags remain properly closed.
• Verified clean git history and conventional commit formatting.

[cb-heimdall]

🟡 Heimdall Review Status

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