[NFC][LangRef] Update description for FuncFlags

Add the additional flags from D36850 as well as noInline/alwaysInline from previous changes.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D111600

Author: modiking

llvm/docs/LangRef.rst

@@ -7471,7 +7471,7 @@ The optional ``FuncFlags`` field looks like:
 
 .. code-block:: text
 
-    funcFlags: (readNone: 0, readOnly: 0, noRecurse: 0, returnDoesNotAlias: 0)
+    funcFlags: (readNone: 0, readOnly: 0, noRecurse: 0, returnDoesNotAlias: 0, noInline: 0, alwaysInline: 0, noUnwind: 1, mayThrow: 0, hasUnknownCall: 0)
 
 If unspecified, flags are assumed to hold the conservative ``false`` value of
 ``0``.