Add LLVM file types and extensions as well as extensions used by LLVM

in various places.

This includes the LLVM textual IR (`.ll`), machine IR (`.mir`) generated
bitcode files (`.bc`), a custom language used in LLVM's implementation
called "TableGen" (`.td`), and C++ extensions used for generated code
and X-macro files (`.def` and `.inc`).

Bitcode files are treated similarly to object files, although that is
a bit odd. They are somewhere between archives and object files in terms
of utility, but they most often show up as intermediate files. When
being packaged and used, they are more commonly placed into an archive,
so this seems the least confusing scheme to me.

config/filetypes.yml

@@ -104,7 +104,7 @@ programming:
     crystal: [.cr]
     csharp: [.cs, .csx]
     css: [css]
-    cxx: [.c, .cpp, .cc, .cp, .cxx, .c++, .h, .hh, .hpp, .hxx, .h++, .inl, .ipp]
+    cxx: [.c, .cpp, .cc, .cp, .cxx, .c++, .h, .hh, .hpp, .hxx, .h++, .inc, .inl, .ipp, .def]
     d: [.d, .di]
     dart: [.dart]
     diff: [.diff, .patch]
@@ -123,6 +123,7 @@ programming:
     kotlin: [.kt, .kts]
     latex: [.tex, .ltx]
     less: [.less]
+    llvm: [.ll, .mir]
     lisp: [.lisp, .el]
     lua: [.lua]
     mathematica: [.nb]
@@ -142,6 +143,7 @@ programming:
     shell: [.sh, .bash, .zsh, .fish]
     sql: [.sql]
     swift: [.swift]
+    tablegen: [.td]
     tcl: [.tcl]
     typescript: [.ts, .tsx]
     viml: [.vim]
@@ -376,6 +378,8 @@ unimportant:
       - .sty
       - .synctex.gz
       - .toc
+    llvm:
+      - .bc
 
   other:
     - "~"