Provide code completion for operator definitions and declarations.

...la/toolbox/editor/basic/TLASourceViewerConfiguration.java

.../tla/toolbox/editor/basic/ToolboxCompletionProcessor.java

...rc/org/lamport/tla/toolbox/editor/basic/ToolboxHover.java

...oolbox/editor/basic/handlers/ShowDeclarationsHandler.java

...la/toolbox/editor/basic/pcal/PCalCompletionProcessor.java

.../org/lamport/tla/toolbox/editor/basic/pcal/PCalHover.java

tlatools/src/tla2sany/modanalyzer/SpecObj.java

tlatools/src/tla2sany/semantic/AnyDefNode.java

tlatools/src/tla2sany/semantic/Context.java

tlatools/src/tla2sany/semantic/ModuleNode.java

tlatools/src/tla2sany/semantic/OpDeclNode.java

tlatools/src/tla2sany/semantic/OpDefNode.java

tlatools/src/tla2sany/semantic/SymbolMatcher.java

tlatools/src/tla2sany/semantic/SymbolNode.java