Problem

• Proper nouns should always be capitalized.
• There is more than one correct way to write "Taproot tree" ("Taproot Tree") but we should be uniform and pick one (relates to "Merkle tree" and "Huffman tree" also).

To close this issue

• Fix the spelling of all instances of Taproot tree, Merkle tree, and Huffman tree codebase-wide (rustdocs, code comments, and error strings).
• Fix the capitalization of all instances of Taproot and Merkle (Merkle tree, Merkle root, etc)

Suggested (slightly related) tasks

(dev free to follow these suggestions or not)

• Do not capitalize "tree", use "Merkle tree" and "Taproot tree"
• Remove "tap tree", use "Taproot tree"
• Always capitalize "Taproot" and also "Merkle"

Since rustdocs on error types match the error string closing this issue probably also needs:

• Do not capitalize error strings (or expect messages), unless they start with a proper noun (eg Merkle or Taproot)

Its probably safe to just check the taproot module error strings (and expect statements) while doing closing this issue.