docs: update go/crd docs with semantic version info

[fykaa]

ref: #2521 (comment)

[fykaa]

wrt this, I wanted to understand where this information would fit naturally

Imo, Reference Docs seems as it would be more contextually relevant to developers working directly with CRDs and Go based configurations

[krancour]

We can move this to be inline in the Go/CRD docs.

It turns out it is already mentioned here:

kargo/api/v1alpha1/warehouse_types.go

Lines 241 to 253 in 1a7ab78

	// SemverConstraint specifies constraints on what new image versions are
	// permissible. The value in this field only has any effect when the
	// ImageSelectionStrategy is SemVer or left unspecified (which is implicitly
	// the same as SemVer). This field is also optional. When left unspecified,
	// (and the ImageSelectionStrategy is SemVer or unspecified), there will be no
	// constraints, which means the latest semantically tagged version of an image
	// will always be used. Care should be taken with leaving this field
	// unspecified, as it can lead to the unanticipated rollout of breaking
	// changes. Refer to Image Updater documentation for more details.
	// More info: https://github.com/masterminds/semver#checking-version-constraints
	//
	// +kubebuilder:validation:Optional
	SemverConstraint string `json:"semverConstraint,omitempty" protobuf:"bytes,4,opt,name=semverConstraint"`

(Although the comment about referring to Image Updater documentation ought to be removed. That is leftover from a time when image selection functionality was borrowed from Image Updater. That is no longer the case.)

This is another spot where semver constraints are mentioned -- this time for commit selection:

kargo/api/v1alpha1/warehouse_types.go

Lines 137 to 146 in 1a7ab78

	// SemverConstraint specifies constraints on what new tagged commits are
	// considered in determining the newest commit of interest. The value in this
	// field only has any effect when the CommitSelectionStrategy is SemVer. This
	// field is optional. When left unspecified, there will be no constraints,
	// which means the latest semantically tagged commit will always be used. Care
	// should be taken with leaving this field unspecified, as it can lead to the
	// unanticipated rollout of breaking changes.
	//
	// +kubebuilder:validation:Optional
	SemverConstraint string `json:"semverConstraint,omitempty" protobuf:"bytes,4,opt,name=semverConstraint"`

Run codegen after updating these comments.

Edit: codegen updates the CRDs with the new comments. Eventually, those changes surface here: https://doc.crds.dev/github.com/akuity/kargo

[krancour]

@fykaa you could consider addressing #2880 in tandem with this as they are very closely related.