doc/stdenv: update manual phases execution instructions

Update instructions for manual build phases execution via `nix-shell` to
cover all phases. There is no easy way of getting those commands, so it
makes a sense to have them all properly documented.

Changed files
+8 -3
doc
+8 -3
doc/stdenv/stdenv.chapter.md
···
```
Then, run more phases up until the failure is reached.
-
For example, if the failure is in the build phase, the following phases would be required:
```bash
-
phases="${preConfigurePhases[*]:-} configurePhase ${preBuildPhases[*]:-} buildPhase" genericBuild
```
-
Re-run a single phase as many times as necessary to examine the failure like so:
```bash
phases="buildPhase" genericBuild
···
```
Then, run more phases up until the failure is reached.
+
If the failure is in the build or check phase, the following phases would be required:
```bash
+
phases="${preConfigurePhases[*]:-} configurePhase ${preBuildPhases[*]:-} buildPhase checkPhase" genericBuild
+
```
+
+
Use this command to run all install phases:
+
```bash
+
phases="${preInstallPhases[*]:-} installPhase ${preFixupPhases[*]:-} fixupPhase installCheckPhase" genericBuild
```
+
Single phase can be re-run as many times as necessary to examine the failure like so:
```bash
phases="buildPhase" genericBuild