scripted-diff: s/WITH_MULTIPROCESS/ENABLE_IPC/ in cmake

Rename WITH_MULTIPROCESS to ENABLE_IPC, because ENABLE_IPC is a more accurate
name for the feature. It controls whether the src/ipc/ directory is built and
whether IPC features like -ipcbind, -ipcconnect, and -ipcfd are available. It
does NOT currently enable multiprocess features which are implemented in #10102
building on top of the IPC features. It will also no longer (as of the next
commit), control whether a find_package call is made so the "WITH_" prefix is
also inappropriate.

-BEGIN VERIFY SCRIPT-
git grep -l WITH_MULTIPROCESS | xargs sed -i s/WITH_MULTIPROCESS/ENABLE_IPC/g
-END VERIFY SCRIPT-

doc/translation_process.md

@@ -18,7 +18,7 @@ We use automated scripts to help extract translations in both Qt, and non-Qt sou
 
 To automatically regenerate the `bitcoin_en.ts` file, run the following commands:
 ```sh
-cmake --preset dev-mode -DWITH_USDT=OFF -DWITH_MULTIPROCESS=OFF
+cmake --preset dev-mode -DWITH_USDT=OFF -DENABLE_IPC=OFF
 cmake --build build_dev_mode --target translate
 ```