Add new linter rules for formatting and fix many bugs

[jabraham17]

Adds 4 three linter rules for formatting and fixes many bugs in the parser and other linter rules

New linter rules

• UnattachedElse: warn when else statements are not attached to their preceding curly brace
• UnattachedCatch: warn when catch statements are not attached to their preceding curly brace
• UnattachedCurly: warn when open curly brackets are not on the same line as the block header
• ThenKeywordAndBlock: warn for extra then keyword. resolves [Feature Request]: lint rule for ThenKeywordAndBlock #24867

Bugs fixed

• fixed several issues with IncorrectIndentation
• fixed bad UnusedFormal warnings with interfaces
• fixed the chplcheck test infrastructure not properly testing fixits (leading to many bug making it to main)
• fixed/added curly bracket locations for many nodes
• fixed manage statements having an extra scope creating Block AstNode
• fixed header locations for parenless functions
• fixed segfault unwrapping a null tryStmt.body( ) in chapel-py

Other improvements

• improved chapel-py docs with method calls
• added new chapel-py methods to support working with locations
• added locations for then and else

Parser implementation notes: To make this work, I had to restructure how we parse curly braces locations. Previously, we just stored them in global state and then used them in a few select locations. For many AstNode types, this did not work. One reason is that in several places in the parser we create and destroy Block asts, and this could lose location information. Another reason is that for something like conditionals with multiple curly brace locations, only one of the blocks would get locations. To fix the issue, curly brace locations are stored per statement. We set the global state in block_stmt_body, and then immediately afterwards extract it to the per-statement variable. Future work could remove the global context state for curly braces entirely, but that was more work than I wanted to put into this for this PR.

Testing

• paratest
• start_test test/chplcheck

[Reviewed by @DanilaFe]