Add 010 Editor Binary Template language

[rm-NoobInCoding]

Adds support for 010 Editor Binary Templates (*.bt).

Description

010 Editor Binary Templates describe the layout of a binary file format using a C-like syntax: struct / typedef struct, enum, functions, the usual control flow and preprocessor directives, plus template-specific types (ubyte, uint32, int64, wstring, …), variable attributes (<name=…, format=hex, read=…, optimize=false>) and built-ins (FSeek, FTell, LittleEndian, Printf). 010 Editor executes a template against a file in order to parse and annotate it, so it is classified as programming rather than data.

.bt is not currently claimed by any other entry in languages.yml, so no heuristic is required.

On the grammar: I was unable to find a TextMate, Sublime or VS Code grammar for this language anywhere — the source.bt grammars that exist on GitHub are for unrelated languages (the bt-lang project and various behaviour-tree DSLs). tm_scope is therefore set to source.c, following the existing precedent of B, DTrace, OpenCL, Pro*C, RPC, Unified Parallel C, X BitMap, X PixMap and XS. Because the template syntax is largely a superset of C this highlights well in practice. Happy to change it to tm_scope: none if you would prefer.

On .1sc: 010 Editor scripts (*.1sc) use the same language, but I have deliberately left that extension out as it does not meet the usage requirements (~400 files indexed).

Checklist:

• I am adding a new language.
  • The extension of the new language is used in hundreds of repositories on GitHub.com.
    • Search results for each extension:
      • https://github.com/search?type=code&q=NOT+is%3Afork+path%3A*.bt+%22010+Editor%22
      • https://github.com/search?type=code&q=NOT+is%3Afork+path%3A*.bt+FSeek
      • https://github.com/search?type=code&q=NOT+is%3Afork+path%3A*.bt+LittleEndian
    • Measured via the code search API (extension:bt "010 Editor"): 6,784 files, spread across 128 unique repositories in the first 500 results, with the largest single owner accounting for ~7% of them. FSeek returns 4,056 and LittleEndian 3,512. Note that a bare extension:bt search (23,488) is not a good measure, as .bt is also used in the wild by unrelated behaviour-tree and bt-lang projects — hence the keyword-qualified queries above.
  • I have included a real-world usage sample for all extensions added in this PR:
    • Sample source(s):
      • https://github.com/three-houses-research-team/010-binary-templates/blob/master/Model%20related%20formats/G1M.bt
      • https://github.com/three-houses-research-team/010-binary-templates/blob/master/Archive%20formats/KSLT.bt
      • https://github.com/jandk/valen/blob/main/templates/common/streamdb.bt
    • Sample license(s): MIT — Copyright (c) 2019 Three Houses Research Group (LICENSE)
  • I have added a color
    • Hex value: #ffbe0c
    • Rationale: chosen to reflect the yellow/amber of the 010 Editor application icon, which is predominantly yellow on a dark background. SweetScape does not publish official branding guidelines, so this is an approximation of the product's colour rather than an official brand value.