Use consistent PascalCase for space view class identifiers (#5774)

We used to mix different casing. Using `PascalCase` makes it clear it is
an identifier (NOT a name)

### Checklist
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Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
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* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested the web demo (if applicable):
* Using newly built examples:
[rerun.io/viewer](https://rerun.io/viewer/pr/5774)
* Using examples from latest `main` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/5774?manifest_url=https://app.rerun.io/version/main/examples_manifest.json)
* Using full set of examples from `nightly` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/5774?manifest_url=https://app.rerun.io/version/nightly/examples_manifest.json)
* [x] The PR title and labels are set such as to maximize their
usefulness for the next release's CHANGELOG
* [x] If applicable, add a new check to the [release
checklist](https://github.com/rerun-io/rerun/blob/main/tests/python/release_checklist)!

- [PR Build Summary](https://build.rerun.io/pr/5774)
- [Docs
preview](https://rerun.io/preview/95e556378ad5d0ad093c001ac3420716fb66a925/docs)
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- [Examples
preview](https://rerun.io/preview/95e556378ad5d0ad093c001ac3420716fb66a925/examples)
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crates/re_space_view_bar_chart/src/space_view_class.rs

@@ -15,7 +15,7 @@ pub struct BarChartSpaceView;
 
 impl SpaceViewClass for BarChartSpaceView {
     fn identifier() -> SpaceViewClassIdentifier {
-        "Bar Chart".into()
+        "BarChart".into()
     }
 
     fn display_name(&self) -> &'static str {

crates/re_space_view_text_document/src/space_view_class.rs

@@ -48,7 +48,7 @@ pub struct TextDocumentSpaceView;
 
 impl SpaceViewClass for TextDocumentSpaceView {
     fn identifier() -> SpaceViewClassIdentifier {
-        "Text Document".into()
+        "TextDocument".into()
     }
 
     fn display_name(&self) -> &'static str {

crates/re_space_view_time_series/src/space_view_class.rs

@@ -76,7 +76,7 @@ const DEFAULT_LEGEND_CORNER: egui_plot::Corner = egui_plot::Corner::RightBottom;
 
 impl SpaceViewClass for TimeSeriesSpaceView {
     fn identifier() -> SpaceViewClassIdentifier {
-        "Time Series".into()
+        "TimeSeries".into()
     }
 
     fn display_name(&self) -> &'static str {

crates/re_viewer_context/src/space_view/space_view_class.rs

@@ -59,8 +59,7 @@ impl VisualizableFilterContext for () {
 pub trait SpaceViewClass: Send + Sync {
     /// Identifier string of this space view class.
     ///
-    /// This is similar to [`Self::identifier`] but it can be used without an actual instance of the
-    /// class.
+    /// By convention we use `PascalCase`.
     fn identifier() -> SpaceViewClassIdentifier
     where
         Self: Sized;

crates/re_viewer_context/src/space_view/space_view_class_placeholder.rs

@@ -11,7 +11,7 @@ pub struct SpaceViewClassPlaceholder;
 
 impl SpaceViewClass for SpaceViewClassPlaceholder {
     fn identifier() -> SpaceViewClassIdentifier {
-        "Unknown space view class".into()
+        "UnknownSpaceViewClass".into()
     }
 
     fn display_name(&self) -> &'static str {

examples/rust/custom_space_view/src/color_coordinates_space_view.rs

@@ -69,7 +69,7 @@ impl SpaceViewClass for ColorCoordinatesSpaceView {
     // State type as described above.
 
     fn identifier() -> SpaceViewClassIdentifier {
-        "Color Coordinates".into()
+        "ColorCoordinates".into()
     }
 
     fn display_name(&self) -> &'static str {

rerun_py/rerun_sdk/rerun/blueprint/space_views.py

@@ -29,7 +29,7 @@ def __init__(
             The name of the view.
 
         """
-        super().__init__(class_identifier="Bar Chart", origin=origin, contents=contents, name=name)
+        super().__init__(class_identifier="BarChart", origin=origin, contents=contents, name=name)
 
 
 class Spatial2DView(SpaceView):
@@ -141,7 +141,7 @@ def __init__(
             The name of the view.
 
         """
-        super().__init__(class_identifier="Text Document", origin=origin, contents=contents, name=name)
+        super().__init__(class_identifier="TextDocument", origin=origin, contents=contents, name=name)
 
 
 class TextLogView(SpaceView):
@@ -197,4 +197,4 @@ def __init__(
             The name of the view.
 
         """
-        super().__init__(class_identifier="Time Series", origin=origin, contents=contents, name=name)
+        super().__init__(class_identifier="TimeSeries", origin=origin, contents=contents, name=name)