Closes #4673

* fix pixel offset issue with `DrawRectangleRoundedLinesEx`

* improve fix - (pixel offset issue with `DrawRectangleRoundedLinesEx`)

* revert radius tweak (`DrawRectangleRoundedLines`)

* [rshapes] Remove `DrawRectangleLines()`'s + 1 offset

* ... and replace it with a -/+ 0.5 offset divided by current cam's zoom.

void DrawCircleGradient(int centerX, int centerY, float radius, Color color1, Color color2);
void DrawRectangleGradientV(int posX, int posY, int width, int height, Color color1, Color color2);
void DrawRectangleGradientH(int posX, int posY, int width, int height, Color color1, Color color2);
void DrawRectangleGradientEx(Rectangle rec, Color col1, Color col2, Color col3, Color col4);

Have been changed to:

void DrawCircleGradient(int centerX, int centerY, float radius, Color inner, Color outer);
void DrawRectangleGradientV(int posX, int posY, int width, int height, Color top, Color bottom);
void DrawRectangleGradientH(int posX, int posY, int width, int height, Color left, Color right);
void DrawRectangleGradientEx(Rectangle rec, Color topLeft, Color bottomLeft, Color topRight, Color bottomRight);

* Change some global variables to have internal linkage

* Update rcore.c

* Update rcore.c

* remove function call

* fix

* [rshapes] Fix multisegment Bezier splines.

It seems to me that these functions are wrong, if you step the index by 1 you move to a control point instead of the next segment.

* Fix example shapes/shapes_splines_drawing for bezier splines.

* Draw circles to fill gaps between bezier segments.

* Update raylib_api.* by CI

* make functions that take a pointer to an array take them as const pointers

* Update raylib_api.* by CI

* fix comment alignment.

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Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

* inital function

* working 1

* optimize

* optimized dot product

* simplify

* cleanup

* cleanup

* cleanup

* comment

* var name change

* epsilon

This could be actually very tricky and GPU/drivers dependant...

For consistency, now _almost_ all `Draw*Lines()` functions use `RL_LINES` mode for drawing. It solves the linked issue but it can have other implications, as mentioned in the WARNING comment in `DrawRectangleLines()`.

Side note: `DrawRectangleRoundedLines()` now should be reviewed for consistency.

- Review formatting
 - Improve readability for some functions result return
 - Minimize early returns
 - Align LoadFileData() to UnloadFileData()

* provide access to the shape texture so that shapes can be extended outside of raylib with the same optimizations as internal raylib functions.

* PR feedback, comply with C standards

* oops

* Implement miters in DrawSplineLinear

* Follow raylib style

This change allows more versatile and consistent splines drawing. It also gives more control to advance users to draw splines as individual segments.

RENAMED: `DrawLine<spline_type>()` to `DrawSpline<spline_type>()` for more consistent and clear naming
REVIEWED: Bezier drawing parameters order, more consistent
REVIEWED: Spline-based examples -WIP-

ImageDrawCircleLinesV already existed, so I'm not sure why this was
missing. It is trivial to implement, anyway

- `DrawLineBSpline()`
 - `DrawLineCatmullRom()`