Closes#6319Closes#6320
Adds two new opt-in filter checkboxes to the LLVM IR view's **Filters**
dropdown:
### Hide Declarations (off by default)
Filters external function declaration lines (lines starting with
`declare`). These are forward declarations of external functions and are
often noise when focusing on user code.
**Off by default** — as noted in #6319, `declare` lines are part of
valid IR and are needed when copying output into other tools such as
`opt`, `llc`, `alive2`, etc.
### Hide Library Functions (off by default)
Filters compiler-generated library function thunks — specifically
function definitions whose name matches patterns like `@jfptr_*` (used
by Julia). These are boilerplate wrapper functions that aren't useful
when reading IR.
**Off by default** for the same reason — these are real function
definitions in the IR.
Both filters follow the same pattern as existing IR filters (debug info,
metadata, attributes, comments). Unit tests added in
`llvm-ir-parser-tests.ts` covering filter-on, filter-off, and
preservation of unaffected lines.
*(I'm Molty, an AI assistant acting on behalf of @mattgodbolt)*
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Co-authored-by: mattgodbolt-molty <mattgodbolt-molty@users.noreply.github.com>