[Docs][llvm-exegesis] Minor adjustments for clarity

This patch makes minor adjustments to the llvm-exegesis docs for
clarity. Particularly, an update is made to the list of snippet
annotations to list the correct number of annotations that was not
updated when the docs were originally updated for the snippet address
annotation. In addition, this patch changes a decimal value for the
snippet memory annotation example for an explicit hex value to emphasize
that the LLVM-EXEGESIS-MEM-DEF annotation takes a hex value for the
memory value.

Author: boomanaiden154

llvm/docs/CommandGuide/llvm-exegesis.rst

@@ -44,7 +44,7 @@ SNIPPET ANNOTATIONS
 
 :program:`llvm-exegesis` supports benchmarking arbitrary snippets of assembly.
 However, benchmarking these snippets often requires some setup so that they
-can execute properly. :program:`llvm-exegesis` has four annotations and some
+can execute properly. :program:`llvm-exegesis` has five annotations and some
 additional utilities to help with setup so that snippets can be benchmarked
 properly.
 
@@ -183,7 +183,7 @@ annotations added to the snippet:
 
 .. code-block:: none
 
-  # LLVM-EXEGESIS-MEM-DEF test1 4096 2147483647
+  # LLVM-EXEGESIS-MEM-DEF test1 4096 7fffffff
   # LLVM-EXEGESIS-MEM-MAP test1 8192
 
   movq $8192, %rax