[configuration] Add example using hexadecimal notation (open-telemetry#3975)

Updates open-telemetry#3959

## Changes

Adds example for using an integer in hexadecimal notation. The intention
is to show the difference when quoting vs not quoting and make explicit
that quoting means keeping the original representation (we already have
the `true` example but this one has two different representations).

I think this is already implied by the text so this is only a change in
the example.

* [x] Related issues open-telemetry#3959, part of open-telemetry#3963

---------

Co-authored-by: Robert Pająk <[email protected]>

Author: mx-psi

specification/configuration/file-configuration.md

@@ -120,6 +120,7 @@ export STRING_VALUE="value"
 export BOOL_VALUE="true"
 export INT_VALUE="1"
 export FLOAT_VALUE="1.1"
+export HEX_VALUE="0xdeadbeef"                         # A valid integer value written in hexadecimal
 export INVALID_MAP_VALUE="value\nkey:value"           # An invalid attempt to inject a map key into the YAML
 export DO_NOT_REPLACE_ME="Never use this value"       # An unused environment variable
 export REPLACE_ME='${DO_NOT_REPLACE_ME}'              # A valid replacement text, used verbatim, not replaced with "Never use this value"
@@ -130,9 +131,11 @@ string_key: ${STRING_VALUE}                           # Valid reference to STRIN
 env_string_key: ${env:STRING_VALUE}                   # Valid reference to STRING_VALUE
 other_string_key: "${STRING_VALUE}"                   # Valid reference to STRING_VALUE inside double quotes
 another_string_key: "${BOOL_VALUE}"                   # Valid reference to BOOL_VALUE inside double quotes
+string_key_with_quoted_hex_value: "${HEX_VALUE}"      # Valid reference to HEX_VALUE inside double quotes
 yet_another_string_key: ${INVALID_MAP_VALUE}          # Valid reference to INVALID_MAP_VALUE, but YAML structure from INVALID_MAP_VALUE MUST NOT be injected
 bool_key: ${BOOL_VALUE}                               # Valid reference to BOOL_VALUE
 int_key: ${INT_VALUE}                                 # Valid reference to INT_VALUE
+int_key_with_unquoted_hex_value: ${HEX_VALUE}         # Valid reference to HEX_VALUE without quotes
 float_key: ${FLOAT_VALUE}                             # Valid reference to FLOAT_VALUE
 combo_string_key: foo ${STRING_VALUE} ${FLOAT_VALUE}  # Valid reference to STRING_VALUE and FLOAT_VALUE
 string_key_with_default: ${UNDEFINED_KEY:-fallback}   # UNDEFINED_KEY is not defined but a default value is included
@@ -145,19 +148,21 @@ recursive_key: ${REPLACE_ME}                          # Valid reference to REPLA
 Environment variable substitution results in the following YAML:
 
 ```yaml
-string_key: value                           # Interpreted as type string, tag URI tag:yaml.org,2002:str
-env_string_key: value                       # Interpreted as type string, tag URI tag:yaml.org,2002:str
-other_string_key: "value"                   # Interpreted as type string, tag URI tag:yaml.org,2002:str
-another_string_key: "true"                  # Interpreted as type string, tag URI tag:yaml.org,2002:str
-yet_another_string_key: "value\nkey:value"  # Interpreted as type string, tag URI tag:yaml.org,2002:str
-bool_key: true                              # Interpreted as type bool, tag URI tag:yaml.org,2002:bool
-int_key: 1                                  # Interpreted as type int, tag URI tag:yaml.org,2002:int
-float_key: 1.1                              # Interpreted as type float, tag URI tag:yaml.org,2002:float
-combo_string_key: foo value 1.1             # Interpreted as type string, tag URI tag:yaml.org,2002:str
-string_key_with_default: fallback           # Interpreted as type string, tag URI tag:yaml.org,2002:str
-undefined_key:                              # Interpreted as type null, tag URI tag:yaml.org,2002:null
-${STRING_VALUE}: value                      # Interpreted as type string, tag URI tag:yaml.org,2002:str
-recursive_key: ${DO_NOT_REPLACE_ME}         # Interpreted as type string, tag URI tag:yaml.org,2002:str
+string_key: value                              # Interpreted as type string, tag URI tag:yaml.org,2002:str
+env_string_key: value                          # Interpreted as type string, tag URI tag:yaml.org,2002:str
+other_string_key: "value"                      # Interpreted as type string, tag URI tag:yaml.org,2002:str
+another_string_key: "true"                     # Interpreted as type string, tag URI tag:yaml.org,2002:str
+string_key_with_quoted_hex_value: "0xdeadbeef" # Interpreted as type string, tag URI tag:yaml.org,2002:str
+yet_another_string_key: "value\nkey:value"     # Interpreted as type string, tag URI tag:yaml.org,2002:str
+bool_key: true                                 # Interpreted as type bool, tag URI tag:yaml.org,2002:bool
+int_key: 1                                     # Interpreted as type int, tag URI tag:yaml.org,2002:int
+int_key_with_unquoted_hex_value: 3735928559    # Interpreted as type int, tag URI tag:yaml.org,2002:int
+float_key: 1.1                                 # Interpreted as type float, tag URI tag:yaml.org,2002:float
+combo_string_key: foo value 1.1                # Interpreted as type string, tag URI tag:yaml.org,2002:str
+string_key_with_default: fallback              # Interpreted as type string, tag URI tag:yaml.org,2002:str
+undefined_key:                                 # Interpreted as type null, tag URI tag:yaml.org,2002:null
+${STRING_VALUE}: value                         # Interpreted as type string, tag URI tag:yaml.org,2002:str
+recursive_key: ${DO_NOT_REPLACE_ME}            # Interpreted as type string, tag URI tag:yaml.org,2002:str
 ```
 
 ## SDK Configuration