[ELF][CHERI] Tweak error message to be clearer and have better style

Author: jrtc27

lld/ELF/SyntheticSections.h

@@ -554,11 +554,10 @@ class RelocationBaseSection : public SyntheticSection {
       expr = R_ADDEND;
       if (sym.isFunc() && addend != 0) {
         auto diag = Warn(ctx);
-        diag << "got capability relocation with non-zero addend (0x"
-             << llvm::utohexstr(addend)
-             << ") against function "
+        diag << "capability relocation with non-zero addend (0x"
+             << llvm::utohexstr(addend) << ") against preemptible function "
              << toStr(ctx, sym)
-             << ". This may not be supported by the runtime linker.";
+             << "; this may not be supported by the runtime linker.";
         printLocationMessage(diag, sec, sym, offsetInSec);
       }
     }

lld/test/ELF/cheri/riscv/preemptible-func-addend.s

@@ -19,7 +19,7 @@ global:
   .data
 foo:
   .chericap local + 1
-  # CHECK: warning: got capability relocation with non-zero addend (0x1) against function global. This may not be supported by the runtime linker.
+  # CHECK: warning: capability relocation with non-zero addend (0x1) against preemptible function global; this may not be supported by the runtime linker
   .chericap global + 1
-  # CHECK: warning: got capability relocation with non-zero addend (0x1) against function undef. This may not be supported by the runtime linker.
+  # CHECK: warning: capability relocation with non-zero addend (0x1) against preemptible function undef; this may not be supported by the runtime linker
   .chericap undef + 1