Update specification

Author: GlebChili

docs/specification.md

@@ -15,18 +15,18 @@ To generate a version number `GmodNET.VersionTool` takes a version JSON file of
 ```
 within git repository, where `"Version"` key MUST correspond to a [Semantic Versioning 2.0.0](https://semver.org/spec/v2.0.0.html) compatible version number value and `"Codename"` key MAY correspond to a string value which, if specified, MUST be a single word of ASCII alphanumerics and hyphens [0-9A-Za-z-].
 
-The resulting version number has the form `[FullVersion]+codename.[codename from version JSON file].[tag or branch or pull].[tag or branch or pull request name].commit.[first 7 symbols of hexadecimal representation of git commit hash].[any additional metadata provided in a "Version" key-value pair of the version JSON file]` where `[FullVersion]` is computed as follows: if the `[version]` value of the `"Version"` key of the version JSON file DOES NOT contain pre-release identifier as described in the [item 9 of the Semantic Versioning 2.0.0 specification](https://semver.org/spec/v2.0.0.html#spec-item-9) then `[FullVersion]` is equal to `[version]`, if the `[version]` value of the `"Version"` key of the version JSON file DOES contain pre-release identifier then `[FullVersion]` equals `[version].[year].[month (numerically)].[day].[hour].[second]` where date and time are date and time of the git commit in UTC. `codename.[codename from version JSON file]` can be dropped if there is no codename specified in the version JSON file.
+The resulting version number has the form `[FullVersion]+codename.[codename from version JSON file].head.[git head name].commit.[first 7 symbols of hexadecimal representation of git commit hash].[any additional metadata provided in a "Version" key-value pair of the version JSON file]` where `[FullVersion]` is computed as follows: if the `[version]` value of the `"Version"` key of the version JSON file DOES NOT contain pre-release identifier as described in the [item 9 of the Semantic Versioning 2.0.0 specification](https://semver.org/spec/v2.0.0.html#spec-item-9) then `[FullVersion]` is equal to `[version]`, if the `[version]` value of the `"Version"` key of the version JSON file DOES contain pre-release identifier then `[FullVersion]` equals `[version].[year].[month (numerically)].[day].[hour].[second].[git head name]` where date and time are date and time of the git commit in UTC. `codename.[codename from version JSON file]` can be dropped if there is no codename specified in the version JSON file.
 
 ## Examples of resulting version numbers
 
-`0.6.0-beta.1.2020.8.15.13.24.56+branch.master.commit.7a9b35c` provided git repository at the `master` branch and version JSON file
+`0.6.0-beta.1.2020.8.15.13.24.56.NewFeature+head.NewFeature.commit.7a9b35c` provided git repository head is at the `NewFeature` branch and version JSON file
 ```json
 {
   "Version": "0.6.0-beta.1"
 }
 ```
 
-`1.0.0+codename.Ural.tag.1-0-0.commit.788963a.bugfix14` provided git repository at the `1.0.0` tag and version JSON file
+`1.0.0+codename.Ural.head.master.commit.788963a.bugfix14` provided git repository head is at the `master` branch and version JSON file
 ```json
 {
   "Version": "1.0.0+bugfix14",