Rollup merge of #53768 - RalfJung:gitignore, r=nikomatsakis

move file-extension based .gitignore down to src/

Currently, it for example ignores `*.rlib` files in the repository root -- which I think is wrong; I sometimes get these files when I call rustc directly and I do want them cleaned up, not ignored. No such files are created during the normal build process.

.gitignore

@@ -1,49 +1,3 @@
-*.a
-*.aux
-*.bc
-*.boot
-*.bz2
-*.cmi
-*.cmo
-*.cmx
-*.cp
-*.cps
-*.d
-*.dSYM
-*.def
-*.diff
-*.dll
-*.dylib
-*.elc
-*.epub
-*.exe
-*.fn
-*.html
-*.kdev4
-*.ky
-*.ll
-*.llvm
-*.log
-*.o
-*.orig
-*.out
-*.patch
-*.pdb
-*.pdf
-*.pg
-*.pot
-*.pyc
-*.rej
-*.rlib
-*.rustc
-*.so
-*.swo
-*.swp
-*.tmp
-*.toc
-*.tp
-*.vr
-*.x86
 *~
 .#*
 .DS_Store

src/.gitignore

@@ -0,0 +1,46 @@
+*.a
+*.aux
+*.bc
+*.boot
+*.bz2
+*.cmi
+*.cmo
+*.cmx
+*.cp
+*.cps
+*.d
+*.dSYM
+*.def
+*.diff
+*.dll
+*.dylib
+*.elc
+*.epub
+*.exe
+*.fn
+*.html
+*.kdev4
+*.ky
+*.ll
+*.llvm
+*.log
+*.o
+*.orig
+*.out
+*.patch
+*.pdb
+*.pdf
+*.pg
+*.pot
+*.pyc
+*.rej
+*.rlib
+*.rustc
+*.so
+*.swo
+*.swp
+*.tmp
+*.toc
+*.tp
+*.vr
+*.x86