[llvm] [LangRef] Fix mislabeling in calling convention name (NFC) (PR #111256)

[Antonio Frighetto via llvm-commits]

https://github.com/antoniofrighetto created https://github.com/llvm/llvm-project/pull/111256

We have explained how musttail can be guaranteed when the calling convention is not `swifttailcc` or `tailcc`, ensure what needs to adhere when it is the opposite case (reflect how it is already handled in Verifier).

>From a5323a5d0b35981b4dfbe9a058a5f76c0d734b20 Mon Sep 17 00:00:00 2001
From: Antonio Frighetto <me at antoniofrighetto.com>
Date: Sat, 5 Oct 2024 16:05:28 +0200
Subject: [PATCH] [LangRef] Fix mislabeling in calling convention name (NFC)

We have explained how musttail can be guaranteed when the calling
convention is not `swifttailcc` or `tailcc`, ensure what needs to
adhere when it is the opposite case.
---
 llvm/docs/LangRef.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 6fa35486669d69..1dd4279efcfb68 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -12747,7 +12747,7 @@ This instruction requires several arguments:
    - The caller and callee prototypes must match. Pointer types of parameters
      or return types may differ in pointee type, but not in address space.
 
-  On the other hand, if the calling convention is `swifttailcc` or `swiftcc`:
+  On the other hand, if the calling convention is `swifttailcc` or `tailcc`:
 
    - Only these ABI-impacting attributes attributes are allowed: sret, byval,
      swiftself, and swiftasync.