'optional' mapping description has been  appended

appended 'optional' mapping constraints description
Fix typo
Add missing import to docs
Merge pull request #2277 from strobe/patch-1

'optional' mapping description has been  appended to ScalaForms documentation
Updated IntelliJ setup with missing step

Clarified steps to setup IntelliJ by adding in missing step.
Fixed grammar
Update PlayConsole.md

crtl --> ctrl 
spell fixed
Merge pull request #2300 from kareypowell/patch-1

Fixed grammar
Update ScalaI18N.md

small namespace typo
Merge pull request #2306 from drdamour/patch-2

Update ScalaI18N.md
Merge pull request #2301 from yakmoz/patch-1

Update PlayConsole.md
improve language
small typo fixed
Fix implicitNotFound documentation for Writes and Json.toJson/fromJson.
Update JavaFormHelpers.md
[doc] Update the maximum content length docs

Also add a reference to the Configuration page for unit sizes.
Merge pull request #2329 from wsargent/patch-3

[doc] Update the maximum content length docs
Update JavaGuide2.md

Corrected misspelling of 'Tthat' to 'That'
Merge pull request #2344 from adamtrousdale/patch-1

Update JavaGuide2.md
Ensured all java enhanced classes are updated in cache

Since the Scala incremental compiler also does incremental compilation
for Java sources, when they are touched by the properties enhancer the
cache also has to be updated for them.