[clang-tools-extra] [clangd] Extract to Function: mark unmodified captured parameters const (PR #225666)

[Christian Kandeler via cfe-commits]

ckandeler wrote:

> I'll come back with some numbers shortly.

Linux, release build, CLANGD_TIDY_CHECKS=OFF:

| | before | with patch | delta |
|---|---:|---:|---:|
| unstripped | 71,311,024 B (68.0 MiB) | 71,722,032 B (68.4 MiB) | +411,008 B (~401 KiB, +0.58%) |
| stripped | 59,625,576 B (56.87 MiB) | 59,892,968 B (57.11 MiB) | +267,392 B (~261 KiB, +0.45%) |
| `.text` (via `size`) | 58,201,662 B | 58,459,234 B | +257,572 B (~251.5 KiB) |


https://github.com/llvm/llvm-project/pull/225666