Auto merge of #141372 - khuey:ir_call_dbg_loc, r=jieyouxu

Use the fn_span when emitting function calls for better debug info.

This especially improves the developer experience for long chains of function calls that span multiple lines, which is common with builder patterns, chains of iterator/future combinators, etc.

try-job: armhf-gnu
try-job: test-various
try-job: x86_64-msvc-1
try-job: arm-android

r? `@jieyouxu`

Author: bors