docs: update headings for shutdown/boot sections (#488)

Lowered the heading level for the "Shutdown Configuration" and "Boot Configuration" sections from H2 (##) to H3 (###) to improve document heading hierarchy.

Signed-off-by: Ryan Johnson <ryan.johnson@broadcom.com>

Author: tenthirtyam

.web-docs/components/builder/vmx/README.md

@@ -391,7 +391,7 @@ wget http://{{ .HTTPIP }}:{{ .HTTPPort }}/foo/bar/preseed.cfg
 <!-- End of code generated from the comments of the HTTPConfig struct in multistep/commonsteps/http_config.go; -->
 
 
-## Shutdown Configuration
+### Shutdown Configuration
 
 **Optional**:
 
@@ -527,7 +527,7 @@ wget http://{{ .HTTPIP }}:{{ .HTTPPort }}/foo/bar/preseed.cfg
 <!-- End of code generated from the comments of the VMXConfig struct in builder/vmware/common/vmx_config.go; -->
 
 
-## Boot Configuration
+### Boot Configuration
 
 <!-- Code generated from the comments of the BootConfig struct in bootcommand/config.go; DO NOT EDIT MANUALLY -->
 

docs/builders/vmx.mdx

@@ -104,7 +104,7 @@ JSON Example:
 
 @include 'packer-plugin-sdk/multistep/commonsteps/HTTPConfig-not-required.mdx'
 
-## Shutdown Configuration
+### Shutdown Configuration
 
 **Optional**:
 
@@ -134,7 +134,7 @@ JSON Example:
 
 @include 'builder/vmware/common/VMXConfig-not-required.mdx'
 
-## Boot Configuration
+### Boot Configuration
 
 @include 'packer-plugin-sdk/bootcommand/BootConfig.mdx'